What is a legal document stating a terminally ill patient's wishes regarding treatments called?

A legal document stating a terminally ill patient's wishes regarding treatments is known as a living will. This document explicitly outlines the types of medical treatments and interventions a patient wishes to receive or not receive in the event that they become unable to communicate their preferences due to their medical condition. The living will is an essential part of advance care planning, allowing individuals to express their healthcare preferences and relieve family members and healthcare providers from making difficult decisions during emotional and stressful times.

The other options do not serve this purpose. A universal donor card refers to a designation concerning organ donation; an admission sheet is used for registering patients in healthcare facilities and does not pertain to treatment preferences; a medical history form is designed to gather information about a patient's past health and medical conditions, not their wishes regarding future treatments.