All states have statutes allowing individuals to (1) express their health care wishes and/or (2) appoint an agent to see that those wishes are carried out in the event of incapacity. A standard form or set of forms is available in each jurisdiction for the public to use; this post provides a link to a health care directive form or forms from an authoritative source in every state. This post will be updated as better sources become available; please comment below if you come across broken links or better forms or resources than what I currently have: