What is therapy and does it help?

Howdy, Can someone explain to me what happens in a therapy session? Do they provide an agenda or do I need to ask for something? Has therapy helped you manage your autism and adhd, in what ways?

Based on what I've heard from friends/family, it sounds like therapy is not well defined, where each person and each therapist might have a different approach. I've also heard you need to try out different therapists to find one on your wave length. This uncertainty plus the idea of opening up to a stranger, has led me to avoid therapy all my life.

I want to be brave and try but I'm realizing that I am totally clueless. I'm 35, late diagnosed adhd, anxiety, and my dr. suspects lvl1 autism as well. Many struggles in life, jobs, day to day, ect. But doing okay at the moment. Hearing first hand from people who have similar reasons for seeking therapy would be a big help. Thank you for your time!