If you want your e‑mail messages to contain formatting such as multiple fonts, bold text, colored headings, graphics, and links to websites, you can send your messages in Hypertext Markup Language (HTML) format. When creating a message in HTML format, you can use the Formatting toolbar directly above the message composition box to add styles such as bold or italic to your text, change the font, center text, or other options.
Hypertext Markup Language (HTML)
A text markup language used to create documents for the web. HTML defines the structure and layout of a web document by using a variety of tags and attributes.