Your Apex Forms users will primarily be accessing forms as "Tasks" or "Activities" but when you are building your Forms you need to be able to test them.  Testing for new versions of forms initially takes place in the TIP of the application in the development environment. This is the place to do initial testing and development of forms. To promote the testing forms to the next level environment (QA, Stage, Production, etc) you would need to take a snapshot of the process application and then promote it to the next environment using your standard deployment method.

You can read about versioning in this article.