In PBU you can add a custom @domain address to the shortcuts above the keyboard when a guest shares through email. This is useful when for corporate events where many guests have the same email domain, e.g. @laphotoparty.com.
Note: You can also enable this feature when using PPU Kiosk on your Windows tablet. Check out the solution HERE for more details.
Congrats! You're all set with a new custom keyboard email.