GAR emails configuration can be found in a section Settings > General Settings as a separate tab.
In this page you can insert a default 'Cc' email address as well as a default email content.
Here you can also choose the format of the file itself. Attached file can be sent either as PDF or XLS. The format can be switched to a different one before sending GAR in GAR window.
More information regarding GAR functionality in Leon can be found under here.