Gmails confidential mode would be available for all G Suite users from June 25. The Gmail confidential mode makes it possible for the sender of an email to revoke a sent email or even add expiration dates to it. It will also be possible to block printing and forwarding of emails. The feature works with all email providers because these emails wouldnt be containing the actual email. The recipient would be getting an email that contains a link to the Google servers that hosts the email. When the recipient clicks on the link, Google would demand a login from the part of the recipient.”]
Source: https://hackercombat.com/gmails-confidential-mode-for-all-g-suite-users-from-june-25/