Proof of a physical address is required. One document MUST show both your PO Box and physical (residence) address, and one document may show only the PO Box.If you have never provided your physical address, then you'll need a deed or other proof of residency in the state. Anyone can get a P.O. Box. All documents used to establish residency must include: 1. The student's name (or parent's name if student is under 19 and unmarried). The Postal Service requires customers to provide acceptable and current proof of identity to receive specific products or apply for some services. Use the check stub from your most recent paycheck to prove your address. If you've recently moved, go ahead and change your address with your employer first. Apply at a Post Office: Complete pages 3 and 4 and take this whole form to a Post Office most convenient for you.