A PO Box, or Post Office Box, is a secure, locked box located at a post office where individuals or businesses can receive their mail. Instead of having mail delivered to a home or office address, users rent a PO Box to ensure privacy and security. This is especially useful for those who may not have a permanent address or want to keep their home address confidential. To rent a PO Box, customers typically need to fill out an application and provide identification. PO Boxes come in various sizes and can be rented for different time periods, making them a flexible option for receiving mail.