About Doc-To-Help Markup Language

Doc-To-Help Markup Language (D2HML) is a set of predefined styles that you can use to mark up your source documents when performing tasks, such as creating topic links, keywords, groups, and conditional text, as well as inserting variables. You don’t need to learn any special language. Styles are applied with a single click.

When editing Word source documents, you can use the Doc-To-Help ribbon to apply D2HML styles: 

When you apply a D2HML style to text, a hot spot is created.