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. Alameda Mail Boxes Plus. 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. A person may only register to vote at his or her place of residence. A business address or a P.O. box number may only be used as a mailing address. 2201 SHORELINE DR ALAMEDA, CA 94501-6200.