A Power of Attorney is a legal instrument that is used to delegate legal authority to another. The person who signs(executes)a Power of Attorney is called the Principal. The power of Attorney gives legal authority to another person(called an Agent or Attorney-in-Fact) to make property, financial and other legal decisions for the Principal.
A Principal can give an Agent broad legal authority, or very limited authority. The Power of Attorney is frequently used to help in the event of a Principal's illness or disability, or in legal transactions where the principal cannot be present to sign necessary legal documents.