Is okay to leave off return address when I mail off a letter to a friend?

Answer 1

If you know your friend knows your address -- your complete address, including zip code -- then you can leave it off of the heading of your letter, but don't leave it off of the envelope. If your letter goes astray, and the post office can do weird and wonderful things with mail, the letter can be returned to you if it isn't delivered correctly (for example, if it goes to someone with the same house address but on a different street or avenue. .

Answer 2

Yeah. The post office doesn't care as long as the address to the recipient is correct.