Encrypt a message
In a new message, open Options, select Encrypt, then choose Encrypt or Do not forward. Finish the message and send it.
Reading an encrypted message
Microsoft 365 recipients can generally read it in Outlook. External recipients may receive a Read the message link and can sign in or request a one-time passcode.
Before sending
Check the recipient address carefully. Encryption availability depends on your Microsoft 365 account and organisation settings.