There are two essential elements of a valid power of attorney:
Soundness of Mind: The person signing the document must be mentally competent (i.e., understand what is being signed and what it does). In addition, he or she must be acting by choice, without undue pressure from anyone.
Witnesses: In most states, your signature on your power of attorney must be notarized, or at least two adults, unrelated to you and each other, and who are not named as the attorney-in-fact, must witness you sign the power of attorney.
In some states, including North Carolina and South Carolina, you must record the power of attorney with your county recorder's office. Your LegalZoom Power of Attorney will include state-specific instructions to help you finalize and make valid your document.