HTML Area is a Control Type that provides a tool to format text within the field using bold, italics, bulleted and numbered lists and other options. An HTML Area also allows the user to add a link.
NOTE: Using the HTML Area control type when formatting a column, allowing the input of HTML in that column, should be limited to trusted users that will only use it for formatting purposes. Ensure the pages that contain columns with this control type have restricted access. Refer to Set Page Security for WebApp Groups and View Security by Page for more information