You could do a course recognised by one of the professional bodies related to hypnotherapy, including:
- National Council for Hypnotherapy
- The National Hypnotherapy Society
- British Society of Clinical Hypnosis
- General Hypnotherapy Standards Council and General Hypnotherapy Register
Courses usually involve practical workshops, plus self-study and written assignments. You may have an advantage when applying for courses if you have a background in healthcare or counselling.
Some hypnotherapy courses are aimed at qualified psychologists or healthcare professionals. You'll need a relevant degree or professional qualification for these.