Normally, you cannot set text styles or insert pictures in email. However, most newer email applications can display images and text styles in addition to basic alignment and paragraph formatting. This is done with HTML, which is the format that also web pages use.

Some people do not have HTML-capable mail clients, or prefer not to receive HTML-enhanced mail because it is slower to download and display. Because of this, Evolution sends plain text unless you explicitly ask for HTML.

You can change the format of an email message from plain text to HTML in the email composer by choosing FormatHTML from the menu bar.

Alternately, you also can change the first dropdown list below the Subject line from Plain Text to HTML.

To send all your mail as HTML by default, enable EditPreferencesComposer PreferencesDefault BehaviorFormat messages in HTML.