HTML : HTML to users who have indicated that they want to receive their emails in HTML format, and text to everyone else.
text - text-only to everyone
text and HTML - One single email that contains both the HTML and the text-only formats (this 'multi-part message is larger, but is more likely to work for most users). Note: Since version 2.10.5 the "Text and HTML" option is no longer displayed. Instead, all HTML messages will be multi-part messages, i.e. containing both the HTML and the text-only format of the message.
PDF - The text message as a PDF attachment
text and PDF - One email that contains the text only message with a PDF attachment. Note: the PDF version will be a conversion of the text message, not of the HTML message. PDF generation requires that you activate this feature when you install and configure phplist.
See Also
http://www.inmotionhosting.com/support/ ... in-phplist