In the past, some bank credit cards didn't need a password. Just sign your name and pay the waiter. But if you have the password, you can't. You must swipe your card and enter your password. If you are willing to tell others the password, you can, but it is not safe, so most of them have passwords now. There are hand-held POS machines following waiters or places where money is spent. If you check the amount entered by the waiter, you can enter the password, then sign, receive the bill and receive the card.