Trying to understand all the semaglutide names I keep seeing

I started researching semaglutide and quickly became confused by the number of names people mention.

I keep seeing Ozempic, Wegovy, Rybelsus, and different Indian semaglutide brands discussed together. Some people talk about them as if they are the same, while others say they are used differently.

Can someone explain how these medicines are related and what the important differences are? I am especially interested in understanding whether the differences are about the active ingredient, approved use, dose, or something else.