When addressing an envelope the address of the sender should be in the upper left-hand corner of the envelope along with the full legal name. The recipient's address is to be placed in the center of the envelope and the stamp or stamps are to occupy the upper right corner, comprising the totality of writing and substances that should appear on the envelope.
The sender's address is also referred to as the return address and is used in the event that the letter becomes lost or is refused upon delivery. The letter can then be stamped "return to sender" and the return address will be used for that purpose.
The sender's address consists of the full name, which must be the legal name, as well as the city, state and zip code. The state should be rendered as a two-letter postal abbreviation, such as MA for Massachusetts or NH for New Hampshire.
Once the letter is properly addressed, it can be placed in a post office box for mailing. Letter carriers will cancel the stamp to prevent reuse and then deliver the letter to the address printed on the envelope. The entire process relies on accurate addresses and legible penmanship, so care should be taken when addressing an envelope.