The two basic documents that allow you to communicate your wishes for medical care are (1) a living will and a (2) durable power of attorney for health care. It is important to have both and they are personal documents need to be understood.
A living will is a written statement that details the type of care you want as well as the care do you would not want to receive should you become incapacitated.
Powers of Attorney for Health Care
For health care it is also important to have a durable power of attorney. In this document, you appoint a trusted individual to be your health care agent (sometimes called an attorney-in-fact for health care, health care proxy, or surrogate) to make necessary health care decisions for you and to see that doctors and other health care providers give you the type of care you wish to receive.