When you create an email using a drag-and-drop or module-based tool, you’re actually generating an HTML email.
There are two main types of email you can send and receive: plain text emails (these are exactly what they sound like — any email that contains just plain old text with no formatting) and HTML emails, which are formatted and styled using HTML and inline CSS.
HTML emails are easy to spot — most of the styled, multimedia marketing emails in your inbox are HTML emails.