You can define any number of your own variables to use in your project. These user-defined variables are stored with your project, which means that they are only available to the project in which they are defined. However, you can transfer variables between projects with the Export and Import functions (see below).
User-defined variables can be used almost everywhere in your projects: In topics and headers, the Table of Contents, keywords, image captions, link captions, macros, scripts, HTML code objects, HTML templates and PDF templates. See the other topics in this section for details on using variables in these locations.
Variables and Conditional Output (Reference)