Living wills do not require any mandatory legal forms to be filled; however, in order to cement your position, a living will can be supplemented with a traditional will and a health care power of attorney. A health care power of attorney is a legal document that appoints a person of your choice as your authorized agent, usually referred to as a health-care proxy, who can make medical decisions for you when you are not able to. A living will can also be accompanied by records and accounts of medical history, for the doctor to be able to get a fair idea of the patient's background.