All HTML headings, <h1> through <h6> are available.
h1. Heading 1
h2. Heading 2
h3. Heading 3
h4. Heading 4
h5. Heading 5
h6. Heading 6
To use the headings just type the following code in your text editor. Make sure the code is added in the html mode.
<h1>...</h1>