To ensure you can easily verify a sender is the actual sender of an Email in Apple Mail (macOS only) you can choose to always show the sender’s email address.
To enable this do the following:
Open Mail > Preferences > Viewing > untick “Use Smart Addresses” checkbox.
If it is unchecked already and sender’s email addresses are not showing, then do the following:
- check the box, close preferences, close Apple Mail.
- next open Apple Mail > Preferences > Viewing > untick “Use Smart Addresses”
- next close preferences, close Apple Mail
- open Apple Mail once more and sender’s email address will show.