The basic components of a template are: (1) the template’s name (will not appear in the email), (2) the email subject, and (3) the email body. A template can be saved (4) only once all of these inputs have been filled with some kind of content.
In addition to simple text, you can also add:
Inline images (“1” in image below), Tables (“2” in image below), Attachments (“3” in image below), HTML from a file (“4” in image below)