When writing a P.O. box number, use this format: Title, Department, or Department Name Post Office Box 123, Name of City, State, Zip If your mail is not formatted properly, the carrier may not deliver it.
Correct format for a P.O. box when the letter recipient actually resides elsewhere:
Name Surname
Home Streets and Postal Codes
P.O. Box 123
Location (City, State, ZIP)
When you include both addresses on a letter or package, you’re telling the mail carrier that the person at the physical address can also be reached at the P.O. box. A actual address may not be provided, however, because P.O. boxes are sometimes utilised for anonymity.