Therapy, and consequently the background and training of the therapist you see, is broadly subdivided into 2 different fields:

1) what I refer to as "psychiatric" therapy, with a specifically "medical" way of doing things. It's based on diagnosis and pathology, with a focus on treating the underlying causes of mental health problems. This typically amounts to chemical intervention. The provider will always be someone with a medical license, typically an M.D. or PsyD, although it can also be an RN or PA; someone who can prescribe drugs. While not always the case, talking with them is generally limited in scope to what is necessary to provide a diagnosis and appropriate medication management. It's normal to have appointments on a monthly basis initially, often stretching to a brief visit every 3 months as one's condition stabilizes. You will need to continue to see them for as long as you take medication (although you can sometimes convince a primary care physician to take over medication management once an effective treatment regimen is established).

2) what I refer to as "psychological" therapy, this is often in the form of talk therapy, and focuses more on cognitive understanding and behavioral modification, and can even be as simple as having someone listen to your shit, put it into a reasonable perspective, and provide emotional support or even just providing human interaction. Often the provider will have a Master's or Doctorate in psychology, which is NOT a medical degree. While some psychiatric doctors will also handle this type of therapy, it's much more often they'll refer you to someone who does this. It's quite common to see this person for an hour each week, but can be more or less often and may also include group therapy. They focus on teaching coping skills and can provide CBT and the like. Some people may continue to benefit from this therapy and go for years, others may stick around just until they establish the coping skills needed for their situation.

I'm probably over generalizing, but it's uncommon to start out not knowing what to expect at all, so if even one person reads this and benefits, it was worth me writing this long post on my phone at 2 a.m.

I also have a bit of a warning, with either type of therapy, it's not uncommon for patients to think they should see results pretty quickly, and when they don't they will assume it's not working and discontinue treatment or assume their therapist is inept and jump between several in short order. Imo, this is the worst thing someone can do, it may take a few months for medication to show results and more often than not the first few tries can fail to help, and it can literally take years to develop behavioral changes and coping skills to the point they show real benefit. People that give up on therapy too quickly can end up losing all faith in therapy for the rest of their life, and losing that kind of hope can even worsen their problems. I struggled from my late teens and all the way into my 30s before I really began to really feel like I hit an appropriate balance in daily life, and that isn't guaranteed. However now if I fall apart, I can put myself back together in a matter of days instead of wallowing for years.