Gmails has this function to send 'confidential emails' where you can set an expiration date and a phone number to the recipient receive a pin code to read the message
https://support.google.com/mail/answer/7674059?co=GENIE.Platform%3DDesktop&hl=en
This is a very useful tool to share sensitive information and there is a lot of people who don't know about it
Just testing this server
Joined Feb 2020
