Technical format in which an email is sent. The usual formats are text, HTML and Multipart.
An email in text format contains only text. Formatting (different font sizes, font types, images, graphics, etc.) is not possible.
An HTML email is written in the familiar page description language (PDL) HTML, so it strongly resembles a web page. Therefore, HTML emails can contain graphics. This gives a clear design advantage over plain text emails.
Emails sent as multipart, are emails send simultaneously in multiple email formats (e.g. text and HTML). The email client of the recipient determines which version will be displayed. With old or restrictive set email clients, at least the text version will be displayed. This way ensures that the recipient always receives a readable email.