If it is China Merchants Bank CARCARCARD car credit card (1 standard large card+1 special-shaped small card), you need to open the card separately. Unified account management of personal credit card. You can share the same credit line, generate bills and repay them to any card in your name. 1 standard large card+1 irregular small cards are all master cards, with the same inquiry password, and the transaction password is set separately by card.