I read at SSA online that when one applies for retirement benefits online, they will ask you to mail them any necessary documentation such as W2 forms (copy okay) and a birth certificate (must be the original) and they will advise you of where to send them. They will return by mail the birth certificate. However, when I recently applied for retirement benefits online, nothing was said about mailing in any sort of documentation. Is it not always required for some applicants or does this come later in the process? Perhaps I just missed it while filing online?
IF they need something, they will contact you (by mail).
You can speed up knowing whether they need something by registering for a "mySocial Security" account. The notification is posted there long before it arrives in the mail. Same thing for following your benefits letter.