New Outlook supports Microsoft 365 Message Encryption as long as your email server has an Office 365 Enterprise E3 license.

  1. In an email message, choose Options, and then select Encrypt.

  2. Pick the encryption that has the restrictions you want to enforce, such as Encrypt-Only or Do Not Forward.
    In a new message, select Options > Encrypt > Encrypt.

  3. Finish composing your email and then choose Send.