Whilst it doesn't really matter, it is generally written as P.O. Box without the space, though many people simply use 'PO Box' without the period separating the two letters. It really doesn't matter that much as long as the address on the envelope is written clearly and it's easy to understand what is intended to be written on the envelope.
A PO Box is actually a Post Office Box, and this is a lockable box that is used to have mail posted to it. They are generally used by individuals that want their mail taking somewhere else, by businesses and even by organizations like charities and political parties. If the mail is not necessarily for one individual and is or the organization, then the PO Box is a fantastic way of receiving mail without it going directly to one individual.
Different sizes of boxes are available, too. For small businesses and organizations then smaller boxes can be rented for a lesser price - whilst larger boxes can be rented by much larger businesses and organizations to cope with the huge amount of mail that is received on a daily basis. In many places across the world, like African and East Asia, a Post Office Box is the only way that a person can receive mail. This is because there is no service like FedEx, the Royal Mail or Parcel Force. If a letter is sent to a private individual's home, by means of writing it on the front of the envelope, then the letter will be simply sent back to the sender and marked as being unable to be sent. It must instead be sent to a Post Office Box that has been rented out by an individual.
A PO Box is actually a Post Office Box, and this is a lockable box that is used to have mail posted to it. They are generally used by individuals that want their mail taking somewhere else, by businesses and even by organizations like charities and political parties. If the mail is not necessarily for one individual and is or the organization, then the PO Box is a fantastic way of receiving mail without it going directly to one individual.
Different sizes of boxes are available, too. For small businesses and organizations then smaller boxes can be rented for a lesser price - whilst larger boxes can be rented by much larger businesses and organizations to cope with the huge amount of mail that is received on a daily basis. In many places across the world, like African and East Asia, a Post Office Box is the only way that a person can receive mail. This is because there is no service like FedEx, the Royal Mail or Parcel Force. If a letter is sent to a private individual's home, by means of writing it on the front of the envelope, then the letter will be simply sent back to the sender and marked as being unable to be sent. It must instead be sent to a Post Office Box that has been rented out by an individual.
