Need address to send check to pay off apple card
Looking to pay off Apple Card with check in the mail
You must set up a one time payment with an Apple Card support person as described in the section titled "If your iPhone or iPad is unavailable" in the support document you posted from.
Do not send checks to any addresses you find online as they may not be accepted.
Setup the payment, and you will be given an address to send the check to. Only then will they be expecting it, and accept it.
Otherwise, all Apple Card payments should be done through the Wallet app or at https://card.apple.com