When addressing an envelope, the sender should be sure to clearly print or type the correct delivery address parallel to the longest side of the envelope used. The destination, return address and postage must all be on the same side of the envelope.
The senders should use pen or permanent marker so the address is easy to read from a few feet away, as this moves it through the processing equipment faster. The return address must be placed in the upper left corner of the envelope and the stamp in the upper right. The sender needs to make sure there is enough postage on the envelope, or it may be returned. If in doubt, the sender can have it weighed at the nearest post office.