Send S/MIME or Microsoft Purview encrypted emails in Outlook using a work or school account with a qualified Microsoft 365 subscription.

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

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 …

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.

Once you exchange signed mail and install the certificate, you will be able to send encrypted emails. If you can't encrypt, you are missing the recipient's public key.

Information Rights Management (IRM) allows you to specify access permissions to email messages. IRM helps prevent sensitive information from being read, printed, forwarded, or …

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

Your system administrator must install IRM before you can apply restrictions to an email message. If you don't see the Encrypt button on the Options tab, IRM probably isn't set up. In …

Jan 6, 2026 · To prevent the issue, select the Options ribbon, then select Encrypt, and choose Encrypt or Do Not Forward as noted in this article, Send encrypted messages with a Microsoft …