There are several reasons why you might need to forward mail for another person. A roommate might move out, a child might move away, a former homeowner's mail is delivered to you, or a letter is simply addressed incorrectly. The new address of the person must be known in order to forward the mail. The simplest way to forward all mail is to fill out the United States Postal Service's Offical Change of Address form located on the Internet or found at any post office.
Cross out the incorrect street, city, and zip code with a black permanent marker.
Write the new address to the right side of the old.
Write "Forward To:" above the name. Make the letters larger than the original address so it stands out.
Resend the letter as if it were new. No extra postage is required.