Sending Encrypted Email
It is always best to never send confidential information in email. Email, in it native form, is sent in clear text over the internet and can be intercepted by anyone with the knowledge to capture this traffic. If you need to send confidential email you must use the “Encrypt” feature.
Encrypted email never leaves the Microsoft 365 servers. Attachment will also be encrypted.
Create an email as you normal.
Prior to sending click the “Encrypt” button.
This will add the text “...This message is encrypted...”
Click the “Change permissions” link and select the appropriate option for the contents of this email
Click “Send”
If the recipient is another Office 365 user that will be able to read the email as the normally would because the encrypted email never leaves the Microsoft 365 servers.
If the recipient is not an Office 365 user
They will receive an email message with instructions for how to read the encrypted message. If the encrypted message was sent to a Google or Yahoo Mail account, they can authenticate using your Google or Yahoo account or by using a temporary passcode. If the message was sent to a different account (Comcast or AOL, for example) they can use a temporary passcode. The temporary passcode will be sent to them in email.
More details about encrypted email can be found here. Learn about encrypted messages in Outlook.com - Outlook (microsoft.com)