Tags should be used to easily find the modules that are connected by topic or program when you look at the “My Modules” page.

To add a tag to a module, simply enter it in the "Tags" field while creating the module, and hit "Enter". You can add as many tags as you wish, as long as they'll make it easier for you to find the module in the future.

The purpose of tags is to easily find the "grouping" of modules under the same topic, so keep that in mind when choosing your tags.

Here's a quick training video that goes into more detail about tagging: