Fill in the name of the payee. Go to any Post Office location.Take cash, a debit card, or a traveler's check. Inmates are permitted to send and receive letters. Fill in the recipient and your address; for bills, include an account number; sign it; keep proof of payment. When filling out a money order, you'll need some basic information, such as the recipient's name and your address. 1. Fill in the payee's name. Put the payee's name on the line labeled "Pay to the order of" or "Pay to. How can I buy a money order? Payments post immediately to your water account.