Hello, if you apply for a credit card of China Merchants Bank, you can pay it on the website of 12306. Overseas, you can choose the card swiping machine corresponding to the card swiping route according to the credit card organization logo on the credit card (such as VISA, MASTERCARD, JCB, American Express and UnionPay), and you don't need to open the card swiping function. UnionPay line credit card is directly settled in RMB; If you swipe your card on an international line, it will be settled in US dollars. Since the consumption outside the credit card will be settled in US dollars, if the consumption amount is not US dollars, there will be exchange fees between the two currencies. If you brush the UnionPay line or spend US dollars, there will be no settlement procedures.