"Advance directive" is a term that refers to your spoken and written instructions about your future medical care and treatment. It is a collection of documents that spell out what treatments you do or do not want. These papers only discuss medical treatment and are not the same thing as legal or financial documents such as a power of attorney.
There may come a time when you or a family member is seriously injured or very ill and difficult decisions about giving or withholding medical care must be made. Every competent adult has the right to accept or refuse any recommended medical treatment, and documenting your health care choices before you are sick or injured helps your family and physician understand your wishes.