A letter of authority is a specific letter of intent entrusting another to act on your behalf and it must include a heading with detailed information of the sender as well as the intended recipient, a body that clearly indicates who is being given permission and in what capacity and a closing that is signed by all parties with follow-up contact information. The letter of authority should be printed on official letterhead and include the date written and the time period the authorization is valid, notes Write Express.
A letter of authority grants another person or agent to act on another person's behalf. The utmost care must be taken when writing an authority letter with concise, unambiguous language. A letter of authorization is a legally binding contract, according to Black's online law dictionary.