If you use a PO Box, one document must have both the PO Box and physical (residence) address and one document may only contain the PO Box. A PO Box can be used as the mailing address to receive your REAL ID, but your residency document must display a PO Box and physical address.Proof of a physical address is required. 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. 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. All documents used to establish residency must include: 1. The student's name (or parent's name if student is under 19 and unmarried). Apply at a Post Office: Complete pages 3 and 4 and take this whole form to a Post Office most convenient for you.