An Advance Health Care Directive is a legal document that describes your wishes regarding your body (things you would want to tell a doctor about certain treatment you will / will not accept, life sustaining treatment, funerary arrangements, etc.) and it gives another person, referred to as your medical agent or attorney-in-fact, the ability to deal with your personal medical matters (talk to a health care provider, provide informed consent to treatment, authorize a procedure or prescription) in case you ever become mentally or physically incapacitated.