An advance directive is a legal document that states your wishes about medical care if you become unable to communicate or make decisions for yourself. It often includes who should make decisions for you (a health care proxy or durable power of attorney) and which treatments you would or would not want in certain situations. The document can guide doctors and family members to follow your preferences, especially in end-of-life or serious illness scenarios. Common types include living wills and durable powers of attorney for health care, and there are also specific forms like do-not-resuscitate (DNR) orders in some jurisdictions. The exact rules, eligible forms, and enforcement can vary by country or state, so it’s important to check local laws and healthcare guidelines where you live.