You can add custom Group Labels (Pro5 & Pro6), custom Slide Labels, and custom Library Categories in ProPresenter. To do this, open ProPresenter's Preferences and go to the Labels tab. You can also right-click on a slide to add custom labels, or right-click on a presentation in the library to add a custom category.
This article deals with our legacy product, ProPresenter 6. For the ProPresenter 7 Knowledge Base, click HERE.