Check that the money order amount is correct. Forms of payment accepted on The Postal Store®.VISA®; MasterCard®; Discover®; American Express™. You have to submit the filing fee with a document you want to file. Use funds in the form of a personal check, money order or cashier's check. Said funds must come from a US (domestic) bank and must be payable in US dollars. Yes, all AMEX card bills can be paid via money order. I have done this for quite some time. You may use your Mastercard®, Visa®, Discover Card®, or American Express® to make a child support payment. If not, consider ordering a birth, death or marriage certificate from the Register of Deeds in the county of the event.