All emails that get sent through advantage mailer are HTML based documents, this is so that the email can be tailed and designed as you want it to be, including any images tables of information, bold and formatted text and so on.
When composing an new email newsletter, you can use out WYSIWYG editor to create your email newsletter. This generates all of the necessary HTML code needed to send your email.
When your email is sent, advantage mailer automatically generates a 'text only' version of your email and sends it along with your formatted, designed email at the same time in one multi-part email, this is so that members who are not able to view a HTML or rich text email can still read your emails.
If you would like to specify your own text only version of your email, you can create and upload your text at the same time as you compose your regular email.