if it's a single-currency credit card, when you swipe your card, it's already converted into RMB. You can repay in RMB directly in the card.

if it's a dual-currency credit card, if you swipe the US dollar (visa or master or jcb), it will be converted into US dollars. There are US dollars deposited in US dollars, and there are no US dollars deposited in excess RMB, and then call customer service to purchase foreign exchange for repayment. Or bind the CCB savings card to automatically purchase foreign exchange for repayment.