Email Templates – HTML or Plain Text?

You should setup both a HTML and a text version of your email in each tab. The reason for this is that the email system then sends both the HTML version and the text version to a recipient. When it arrives at the recipient, depending on their email settings, the text based email or the HTML will get displayed.

If you don't set up a Plain Text version and the recipient can only receive Plain Text email, they will get a blank email.