Depending on your state, you must either have your health care directive signed by two witnesses or notarized by a notary public -- and in some cases, both. You can learn your state's laws here: Finalization Requirements for Health Care Directives . In all states, you must sign the document yourself or have someone sign on your behalf.
When you make a health care directive with WillMaker, your document will print out with state-specific instructions that tell you exactly what to do.
Learn more about health care directives generally on Nolo's Living Wills and Medical Powers of Attorney section.