How Occupational Therapy helps mental health

I'm very interested in finding out in what settings is art therapy used by an occupational therapist. A licensed ATR performs that..I've never seen OTR.
Also, any reference on where relaxation therapy would occur. Again, have NEVER seen or heard of that while working in hospital inpatient or outpatient. I have shadowed occupational therapy in 3 different settings & did not witness this once, nor have I heard by employees this would be an option. Please advise bc I'm very interested

Awesome information!!