Writing the return address on an envelope is very easy, but also very important. You must write it in the correct area or else a number of things could happen. If you write your recipient's address where your return address should be, and your return address is written where your recipient's address should be, you will get your letter mailed back to you. If your return address is not legible, you will not get it back if your recipient's address is incorrect or your postage is wrong and cannot be mailed.
On the side of the envelope that does not have the opening, find the top left corner. Make sure you do not write the address of the person you are mailing it to in this spot, otherwise, they will not receive your letter.
Write your name and full address, including address number, street name, city, state and postcode. If you only have a P.O. box address, write the full address. These should be divided into three lines. The first line would have your name. On the second line directly under the first line, write the address number and street name. Include an apartment or suite number if applicable. On the third line directly under the second line, write your city, followed by a comma, state or state abbreviation, then postcode. The following is a visual example:
Bob Smith 123 Main St. Apt. #2 Citytown, NY 12345
If you are addressing an envelope to go to a different country, remember to write your country's name on a fourth line underneath the line with city, state and postcode. For the United States, you can write U.S.A.