How to Send Secure Email in Outlook: Essential Easy Guide

You’ve got sensitive information—client data, financial records, personal details—and you need to send it via email. The problem? Standard email is about as secure as leaving your front door unlocked. Anyone with basic hacking skills can intercept unencrypted messages. If you’re wondering how to send secure email in Outlook, you’re asking the right question. The good news: Outlook has built-in tools that make this easier than most people think, and I’m going to walk you through every single one.

The stakes are real. Healthcare providers, law firms, and financial institutions face hefty fines if they send unencrypted sensitive data. But even if you’re just a small business owner or freelancer, protecting your client communications is non-negotiable. Outlook gives you multiple ways to lock down your emails—from encryption to expiration dates to password protection. Let’s break down exactly how to use them.

Understanding Email Security in Outlook

Before we jump into the how-to, let’s talk about why this matters. When you send a regular email through Outlook, it travels across the internet like a postcard—anyone handling it can read it. Encryption scrambles that message so only the intended recipient can decode it. Think of it like putting your postcard inside a locked box that only the recipient has the key to.

Outlook offers several layers of security, and understanding the difference between them is crucial. You’ve got encryption (which locks the content), message expiration (which deletes the email after a set time), and access controls (which prevent forwarding or copying). Each serves a different purpose, and sometimes you’ll use them together.

Microsoft 365 users and Outlook on the web have access to more advanced security features than older versions. If you’re still using Outlook 2016 or earlier, some of these options won’t be available. Check your version before assuming everything below will work for you.

Real Talk: If you work in healthcare, finance, or law, your organization probably has specific compliance requirements (HIPAA, GDPR, CCPA). Don’t just rely on Outlook’s built-in tools—check with your IT department first. They may have enterprise-level solutions already in place.

How to Enable Message Encryption in Outlook

This is the gold standard for how to send secure email in Outlook. Message encryption ensures that only the recipient can read your email, even if someone intercepts it in transit.

1. Open Outlook and start composing a new email.
2. Click the Options button (usually three dots) in the compose window.
3. Look for Encrypt or Protect options—the exact label depends on your version.
4. Select Encrypt to enable end-to-end encryption.
5. Your recipient will receive a secure message and may need to authenticate to read it.
6. Hit send and you’re done.

The beauty of this approach is that it works even if your recipient doesn’t use Microsoft 365. They’ll get a link to view the message securely online, no special software required.

1. Start a new email.
2. Go to the Options tab in the ribbon.
3. Click Encrypt in the Permission group.
4. Choose Encrypt-Only or Do Not Forward depending on your needs.
5. Compose your message and send.

The Do Not Forward option is stricter—it prevents the recipient from copying, forwarding, or printing the email. Encrypt-Only is more flexible but still protects the content.

1. Create a new email.
2. Click the Options button.
3. Select Encrypt.
4. Send as normal.

Mac users have fewer options than Windows users, but encryption is still available. If you need advanced features, you might need to switch to Outlook on the web.

Using Outlook’s Encrypt-Only Option

Here’s where things get granular. Outlook gives you different encryption levels, and choosing the right one depends on what you’re protecting.

Encrypt-Only: This encrypts the message but allows the recipient to forward it, copy it, or print it if they want. It’s useful when you trust the recipient but want to protect the email in transit. Use this for internal communications or when working with established partners.

Do Not Forward: This is the lockdown option. Recipients cannot forward, copy, or print the email. It expires automatically (usually after a set time). Use this for highly sensitive information like passwords, financial data, or confidential business plans. Learn more about encryption options in our detailed encryption guide.

Here’s the catch: Do Not Forward is more restrictive, which can frustrate recipients who legitimately need to share the information internally. If you’re sending to a client or external party, explain why the restriction is in place. They’ll understand if you’re protecting their data too.

To apply these settings:

1. Open your email draft.
2. Click Options → Encrypt.
3. Choose your encryption level.
4. Add a disclaimer or note explaining the restriction (optional but helpful).
5. Send.

One pro tip: If you frequently send encrypted emails to the same person or group, create a distribution list and set default encryption rules for it. This saves time and reduces the chance you’ll forget.

Setting Message Expiration Dates

Imagine sending an email with sensitive information, and then realizing three months later that the recipient still has it sitting in their inbox. Message expiration prevents this. You can set emails to automatically delete from the recipient’s mailbox after a specific time period.

This is particularly useful for:

• Time-sensitive information (like temporary passwords or access codes)
• Confidential announcements that shouldn’t be referenced later
• Information that becomes outdated quickly

1. Compose your email.
2. Click Options.
3. Select Encrypt.
4. Look for Expire Access or Set Expiration.
5. Choose a timeframe (typically 1 day to 30 days).
6. Send the email.

After the expiration date, the recipient won’t be able to open the email—it simply becomes inaccessible. This is different from deleting it; the message stays in their mailbox but they can’t read it.

1. Go to File → Info → Manage Rules & Alerts.
2. Create a new rule or edit an existing one.
3. Set conditions for when the rule applies.
4. Add an action to expire the message.

Desktop Outlook’s expiration feature is less intuitive than the web version, but it’s more powerful once you get the hang of it. You can create rules that automatically expire certain types of emails—say, anything marked “Confidential.”

Pro Tip: Always let your recipient know the email will expire. Include a note like “This email expires in 7 days—please save any information you need before then.” Otherwise, they’ll be confused when they can’t open it later.

Marking Emails as Confidential

This is the simplest security measure, but don’t underestimate it. Marking an email as confidential doesn’t encrypt it, but it signals to the recipient (and any mail system handling it) that the content is sensitive.

1. Compose your email.
2. Click Options.
3. Select Sensitivity or Importance.
4. Choose Confidential.
5. Send.

1. Open your draft email.
2. Click the File tab.
3. Select Properties.
4. Under Settings, find Sensitivity.
5. Choose Confidential.
6. Click OK and send.

This marking appears in the email header and can trigger automatic handling rules in your organization. For example, your company might have a rule that automatically adds a footer to all confidential emails reminding recipients not to forward them.

However, here’s the reality: marking something as confidential is more of a courtesy flag than a security measure. It doesn’t prevent someone from forwarding the email. If you need actual protection, use encryption instead.

Using Information Rights Management (IRM)

IRM is Outlook’s enterprise-grade security feature. It’s more powerful than standard encryption because it lets you control exactly what the recipient can do with the email—down to whether they can copy text or take screenshots.

IRM requires your organization to have Azure Information Protection or Microsoft Information Protection set up. If you work for a larger company, your IT team has probably already configured this. If not, you’ll need to contact them to enable it.

1. Compose your email.
2. Go to Options → Encrypt.
3. Select Restrict Access or Do Not Forward.
4. Outlook will apply the IRM policy your organization has configured.
5. Send the email.

The recipient will see a notification that the email is protected and may need to authenticate with their Microsoft account to read it. They’ll also see a list of restrictions—what they can and can’t do with the message.

IRM is overkill for most everyday emails, but it’s essential for truly sensitive information. Think legal documents, financial records, or strategic plans. If you’ve already sent an email you shouldn’t have, check out our guide on retracting emails in Outlook.

Warning: IRM-protected emails can be difficult for recipients to manage. They can’t always forward them to colleagues, and some mobile devices have trouble opening them. Use IRM sparingly and only when absolutely necessary.

Best Practices for Secure Email in Outlook

Now that you know how to send secure emails, let’s talk about doing it right. Technical security means nothing if you’re sending passwords in the subject line or using weak email addresses.

The subject line is not encrypted, even if the email body is. Anyone with access to your email server can read it. Use vague subject lines like “Confidential Information” instead of “Your Social Security Number: 123-45-6789.”

If you’re sending password-protected emails, make sure the password is complex. Don’t use the recipient’s name or common words. And never send the password in the same email—call them or use a separate communication channel.

This is huge. A single typo and your secure email goes to the wrong person. Outlook’s auto-complete can help, but double-check every address before hitting send. Better yet, create a contact for important recipients so you don’t have to type their address manually.

Many companies have rules about what information can be emailed, encrypted or not. Check your employee handbook or IT policies. Some organizations prohibit sending certain data via email entirely, even with encryption.

Don’t encrypt one email to a client and send the next one unencrypted. Establish a pattern. If you’re handling sensitive information, encrypt everything related to it. This reduces the chance of accidentally sending something unprotected.

If you’re using encryption for the first time, send a test email to a colleague. Make sure they can open it, understand how to authenticate, and know what to do with it. This prevents confusion when you send the real thing.

Microsoft regularly patches security vulnerabilities in Outlook. Keep your software updated to ensure you’re using the latest encryption standards. Check Microsoft’s official support site for the latest updates.

Not everyone is tech-savvy. If you’re sending encrypted emails to someone who rarely uses email, include clear instructions on how to open the message. A brief note like “You’ll receive a link to open this secure email—just click it and follow the prompts” goes a long way.

Troubleshooting Common Issues

This usually means your organization hasn’t enabled encryption or you’re using an older version of Outlook. Check with your IT department. If you’re using Outlook on the web, make sure you’re logged into a Microsoft 365 account, not a personal Outlook.com account (though Outlook.com does support encryption too).

First, ask them to check their spam folder—sometimes encrypted emails get flagged. If it’s not there, they may need to authenticate with a Microsoft account. If they don’t have one, they can create a free one. If they’re still having trouble, send them the email again without encryption and ask if that works. This helps isolate whether the issue is with encryption or their email account.

Unfortunately, you can’t unsend an encrypted email the way you can with a regular one. You can try to retract it using Outlook’s recall feature, but this only works if the recipient hasn’t opened it yet. Your best bet is to immediately email them and ask them to disregard the previous message and not open it.

Encryption adds a tiny bit of processing time, but it shouldn’t be noticeable. If your Outlook is running slowly, it’s probably not the encryption. Check if you have too many emails in your inbox, too many plugins running, or if your computer just needs more RAM.

You might have set the expiration too short. Default is usually 7 days, but you can extend it to 30 days or more. Check your settings and adjust. Also, remind recipients to save important information before expiration—don’t rely on them remembering to do it.

Create a folder called “Encrypted Emails” and move copies of encrypted messages there. Or use Outlook’s search feature with the filter “Encrypted: Yes” to find them later. This is helpful for compliance and record-keeping.

Frequently Asked Questions

Does Outlook encryption work with Gmail or other email providers?

– Yes and no. If you encrypt an email in Outlook and send it to a Gmail user, they’ll receive a link to view the message securely online. They don’t need to use Outlook or Microsoft 365. However, some advanced features like “Do Not Forward” may have limited functionality with non-Microsoft accounts. The recipient will still be able to access the message, but they might have more flexibility to save or print it than they would with a Microsoft 365 account.

Is encryption the same as a password-protected email?

– Not exactly. Encryption scrambles the message so it’s unreadable without a decryption key. Password protection adds an extra layer where the recipient needs to enter a password to unlock the message. Outlook’s encryption includes password protection by default, but you can’t set a custom password. If you need a custom password, you’ll need to use a third-party tool or your organization’s IRM system.

Can I encrypt emails to external recipients?

– Yes. Outlook’s encryption works with anyone, regardless of whether they use Microsoft 365 or a different email provider. External recipients will receive a link to view the secure message online. They may need to create a free Microsoft account or authenticate with their existing account, but it’s straightforward.

What happens if the recipient doesn’t authenticate?

– If they don’t authenticate within the time limit (usually a few days), the email becomes inaccessible. They can request a new link, but they’ll need to go through the authentication process again. This is actually a security feature—it prevents unauthorized access.

Can I encrypt emails on my phone?

– The Outlook mobile app has limited encryption support. You can encrypt emails on iPhone and Android, but the options are more basic than the desktop or web versions. For full control over encryption settings, use Outlook on the web or desktop.

Is there a difference between encrypting and marking as confidential?

– Absolutely. Marking as confidential is just a flag—it doesn’t actually protect the content. Encryption scrambles the message so only the intended recipient can read it. Always use encryption for truly sensitive information, not just the confidential flag.

Can I encrypt emails to a distribution list?

– Yes, but be careful. When you encrypt an email to a distribution list, each member gets their own encrypted copy. If the list has external members, they’ll all receive the secure email link. Make sure you trust everyone on the list before sending sensitive information.

What if my organization doesn’t allow encryption?

– Some organizations disable encryption for compliance or policy reasons. If that’s the case, talk to your IT department about alternative solutions. They might have a different secure email system in place, or they might allow encryption for specific types of communications.

How long does encryption last?

– Encryption is permanent. Once a message is encrypted, it stays encrypted. However, you can set an expiration date so the recipient can only access it for a limited time. After expiration, the message becomes unreadable even if it’s still in their mailbox.

Can I encrypt attachments separately from the email body?

– No. When you encrypt an Outlook email, the entire message—including attachments—is encrypted together. You can’t encrypt just the attachment while leaving the body unencrypted. This is actually a good thing because it keeps everything secure and prevents confusion.

Learning how to send secure email in Outlook is one of the most important skills you can develop in today’s digital world. Whether you’re protecting client data, financial information, or just personal details, Outlook gives you the tools to do it right. Start with basic encryption, understand the different options available, and always think about what level of security your information actually needs. Your recipients—and your peace of mind—will thank you.

For more information on email security best practices, check out resources from OSHA’s data security guidelines and CISA’s email security recommendations. These government resources provide solid foundational advice that applies to all email platforms.