Rich Text Email
Rich text usually means email with formatting such as bold text and lists. Check whether an editor sends HTML or a separate format such as Outlook RTF.
Rich text email usually means a message with formatting such as bold text, lists, and labeled links. The term describes an editing experience as often as a message format: an editor can offer rich text controls and send HTML.
Classic Outlook also has a specific Rich Text Format, or RTF. Microsoft describes it as a legacy format and recommends HTML. See its message-format documentation for the differences between Outlook versions.
Choose formatting for the content
A setup email may need a short numbered list and a link to the next step. A product update may need headings so readers can find the changes that affect them. Neither requires a complex visual template.
Use the editor's preview, then inspect a sent test. Check the actual message format when compatibility matters. The words “rich text” in a toolbar do not tell you which MIME type was sent. Keep instructions understandable if a recipient's client removes formatting.