fwd is a written short form of forward. You meet it most in email, where Fwd: at the start of the subject line means this letter was sent on to you by someone else — it did not start with them. People also type pls fwd this to the team in quick notes. Out loud, almost everyone still says forward, not fwd. The same short form can mean forward in other writing too, such as a note to send something onward, but the mail use is the one students see every day. It is informal on the page; it is not a word you put in a careful school essay.