user-mail-address

user-mail-address is a variable defined in `startup.el'.
Its value is

"artur@Gandalf-Linux"

Documentation:
Full mailing address of this user.
This is initialized with environment variable `EMAIL' or, as a
fallback, using `mail-host-address'. This is done after your
init file is read, in case it sets `mail-host-address'.

You can customize this variable.