Fill in the recipient and your address; for bills, include an account number; sign it; keep proof of payment. Money orders offer a reliable, convenient alternative to cash or a check.Buy and cash money orders at a Western Union location near you. Access details on our services or visit a branch. Never mail a blank money order. We have detailed instructions on how to fill out a money order for guidance. Money orders made easy. This ensures only the recipient can cash the money order. 2. Add Your Address to the Purchaser Section. First, decide how much money you want to send and where the funds will come from (cash, debit or credit card).