Gmail has a confidential mode feature that allows users to send sensitive information to recipients and prevent unauthorized access. Gmail explains:
You can use confidential mode to set an expiration date for messages or revoke access at any time. Recipients of the confidential message will have options to forward, copy, print, and download disabled.
If a Gmail user sends you an email using confidential mode, your viewing experience will differ based on whether you are viewing the message within Gmail itself, or in another email client like Front. Both are simple to use.
How it works
Viewing in Gmail
If you view the email in Gmail, granted that you are also a Gmail user, the message content will show natively in your Gmail inbox until the expiration date.
Viewing in Front
If you view the email in Front, or any other non-Gmail client, you will not see the actual content of the email, but be asked to click a link to View the email.