There are several ways to document what a template is supposed to do: 1. * In some cases it is obvious on the template page itself without special provisions. 2. * It can be explained in text tags. This method allows for such things as adding the template to a template category. 3. * Detailed documentation can be put on the template talk page. This method is typically mixed with the noinclude-strategy on the template page, with a reference to the talk page, and perhaps a summary.