Information used in this article and more information about Office 365 Encryption can be found here: https://docs.microsoft.com/en-us/microsoft-365/compliance/ome
Sending an encrypted email from Office 365 web app
Step 1: Open a new email and click protect. See below.
Step 2: It will default to "Encrypt" If it does not say "Encrypt" like shown below click "Change Permissions". See below.
Step 3: Click on the drop-down menu and choose "Encrypt" from the options then press "Ok". See below.
Sending an encrypted email from Office 365 Outlook or Outlook 2016
Step 1: Open up a new email and navigate to "Options-Encrypt". As seen below.
Step 2: All email accounts set up within Outlook will be listed. Choose the email account you wish to email from by hovering over it and then select either "Encrypt" (encrypts the content of the email) or "Do Not Forward" (encrypts the content of the email and stops receiver from forwarding the email). See below.
Step 3: The below-outlined message confirms that encryption has been applied to the email. See below.
Receiving a protected email inside of Office 365
"Recipients who receive a protected email message sent to an Office 365 account in Outlook 2016 or Outlook on the web, don't have to take any additional action to view the message. It works seamlessly." - docs.microsoft.com
Receiving a protected email outside of Office 365
These are the steps a receiver of an email sent with Office 365 encryption will have to take if they are receiving the email outside of Office 365 e.g a Gmail account.
Step 1: The first email will look like the below, an email outlining that a protected/ encrypted email has been received from an Office 365 tenant. To view the message you must click "Read the message".
Step 2: The address of the sender will be outlined at the top of the page, as seen below. To open the message we recommend you click the "Sign in with One-time passcode" button, again, outlined below.
Step 3: The next page will outline that a one-time passcode has been sent to the email address that the original message was sent to. See below.
Step 4: A new message will be received from Microsoft with a one-time code in. See below. Copy this code.
Step 5: Paste the code received from Microsoft into the one-time passcode box and click "Continue". See below.
Step 6: You will now be able to see the email in its entirety.
Please note that encryption cannot be removed from Office 365 Protected emails.
Information in this article and more information about Office 365 Encryption can be found here: https://docs.microsoft.com/en-us/microsoft-365/compliance/ome