Learn how to use encryption and other security settings to protect messages sent from Outlook.

In an email message, from the ribbon, select Options > More Options. In Message options, you can choose the sensitivity level as well as the read or delivery receipt and S/MIME protection options.

If you have a Microsoft 365 Family or Microsoft 365 Personal subscription, Outlook includes encryption features that let you share your confidential and personal information while ensuring that your email …

You can use encryption and digital signatures in new Outlook, classic Outlook, and Outlook on the web for work or school accounts to increase the security of messages.

In an email message, choose Options, select Encrypt and choose the encryption option that has the restrictions you'd like to enforce, such as Do Not Forward or Encrypt-Only.

To turn S/MIME on: In Outlook, tap the Account control at the top left, then select the Settings button near the bottom left. Tap on the specific account you want to turn S/MIME on for. Tap Security and …

Under Microsoft Outlook Trust Center, select Trust Center Settings. On the Email Security tab, under Encrypted Mail, select the Add digital signature to outgoing messages check box.

Learn how to identify and open encrypted and protected emails no matter what email client you're using.

Outlook uses certificates in cryptographic email messaging to help keep communications secure. You can view your own certificates or those that you receive in email messages.

To apply IRM protection, S/MIME signature and encryption must be removed from the message. The same applies for IRM-protected messages; users can't sign or encrypt them by using S/MIME.