Complete the application form. In this form, you are the principal and the person you give authority to is called the agent.A general power of attorney gives a person the power and authority to act for the principal in all business and personal matters. Completing and Executing the Form. Completing a Power of Attorney form in Maryland requires attention to detail to ensure legality and validity. Obtaining and completing a Maryland Power of Attorney (MD POA) form involves understanding specific steps and critical details. No, a lawyer is not required. The completed Maryland Form 548 should include all identifying information for the taxpayer including: Name(s) Address. Then, you must mail or fax a copy of the power of attorney with the revocation annotation to the Comptroller of Maryland. Completing Form 548.