My guess is that experiences will vary greatly between people, but I can offer you my experience since I was somewhat surprised by how it played out.
When I decided I needed help, I made an appointment with a psychiatrist. Based on assumptions and what I've seen in popular media, I thought they'd want to dig into my past and deep seeded traumas and on and on. When I met with them, they seemed mostly uninterested in the why of my problems. He focused on the actual symptoms that I was experiencing and suggested medications and treatment for them. I was actually embarrassed because I tried to delve into some of those deeper concerns, and he politely guided me back to the negative symptoms I was experiencing.
My treatment ended up being two-fold: chemical and interpersonal. In addition to medication, I was refereed to a talk therapist within the same practice. That is where I was encouraged to explore some of the foundational issues that I felt were negatively contributing to my thought processes and explored new ways of thinking.
My suggestion would be to go in with an open mind, and explore what exactly the practitioner does and how they do it. Don't be self conscious or embarrassed if it doesn't go how you expect. We are laymen, after all, and don't know how these things work on the professional side. Also, be open to the help that is offered, even if it isn't the entire treatment plan that you'll ultimately need. Maybe they'll only offer medical treatment, maybe they'll want to talk to you about deeper trauma. But I think (hope) they will probably be very open to helping you find other resources if they think you need something they don't provide personally.
Best of luck to you. I don't know what issue it is you're seeking help for, but whatever it is I'm glad you're putting yourself out there to get assistance.