High Quality Content by WIKIPEDIA articles! A post office is a facility authorised by a postal system for the posting, receipt, sorting, handling, transmission or delivery of mail. Post offices offer mail-related services such as post office boxes, postage and packaging supplies. In addition, some post offices offer non-postal services such as passport applications and other government forms, car tax purchase, money orders, and banking services. The back rooms of a post office are where mail is processed for delivery. Mail may also be processed in other post offices that are not open to the general public.