Since the American Revolution, the United States Postal, system has been an important element of the Nation. The systems work efficiently to deliver cost effective and timely mail. Once of the functions that the postal system has effectively done is to receive and distribute letters from the USPS drop box, private mails, and other customers that bring the mails from the Post Office. The Portal system then takes charge of the mail and verifies that the addresses are written in a proper format. They also charge the postage, which is the fee for the mail, and it is prepaid. You should address your letter with a three-line address. The three-line address includes the name of the company or person that it is to be delivered.