It’s been rumoured that Google is set to revamp Gmail soon. On top of this, the email client might also soon let users send out self-destructing emails. These emails will “expire” after a set amount of time. The feature is reportedly being called “confidential mode.” If an email has been set to expire, the recipient won’t be able to download, forward, or print said copies of the email after the expiration date. It can last for a few days to even years after. There might also be an option to add a passcode for certain emails, which will be sent to the recipient via text message. There is no indication though if this possible new feature could work with emails sent to non-Gmail users or if there will be end-to-end encryption. We have to wait and see if this feature will come to users.
Source: Android Authority