Big subject.
Poor results in adolescents and the young. Gastric band is falling out of favour leaving gastric sleeve and a bypass operation. Both work by several mechanisms and the choice can only really be made after you have had a proper assessment and full explanation.
There are also various procedures inserting devices into the stomach but their long term benefits are uncertain
The operation needs to be done by a proper bariatric surgeon who works in a proper system so you get follow up. The operation is laparoscopic (keyhole) taking several hours and one night stay. The risks are greater than for some other laparoscopic procedures but long term benefits far outweigh them. You will be on a restricted diet for a period after the operation (weeks depending on what you have and your surgeon) but should then be able to regain your medical.
Hope this is a start