It depends on multiple factors, mostly the state you work in. Licensing differs among states, but generally you will have two options- a supervised level and an independent level. You will do the engage in the same activities, but what differs if you have to practice under ones license or not. There are two other options, some states (like Ohio) don't offer licensing for those with a masters and the other option (which is only valid in one state) is that you can become a licensed psychologist.
For the most part you will be doing the same duties as a psychologist; that is, therapy, assessment, diagnosis, and treatment planning for the most part.