a credit card is a special carrier card issued by a commercial bank to individuals and units, which is used to make purchases from special units and deposit and withdraw cash from banks. It is in the form of a card with the name of the issuing bank, expiration date, number and cardholder's name printed on the front, and a magnetic stripe and signature strip on the back. The credit card we are talking about now generally refers to a debit card only. In layman's terms, credit card is a kind of micro-credit payment tool provided by banks to users. That is, when your shopping needs exceed your ability to pay or you don't want to use cash, you can borrow money from the bank, which doesn't need to pay any interest and handling fees. A credit card is a certificate that the bank promises to lend you money. A credit card will tell you how much money you can borrow from the bank and when you need to pay it back. In addition, you can withdraw cash directly from the ATM machine when there is no money in your credit card.

A check is a sight draft drawn on a bank, which can be regarded as a special case of a draft. The amount of a cheque issued by the drawer shall not exceed the amount of its deposit with the drawee. If the deposit is less than the check amount, the bank will refuse to pay. This kind of check is called a bad check, and the drawer should bear the legal responsibility. To open a checking account and collect checks, you must have reliable credit standing and deposit a certain amount of funds. Checks can be divided into cash checks and transfer checks. Once endorsed, a cheque can be circulated and transferred, which has the function of currency and becomes a credit circulation tool to play the role of circulation means and payment means instead of currency. The use of checks for currency settlement can reduce the circulation of cash and save the cost of currency circulation.

Exchange rate, also known as "foreign exchange market or exchange rate", is the most important adjusting lever in international trade. The ratio of one country's currency to another country's currency is the price of one currency to another. Due to the different names and values of currencies in different countries in the world, one country's currency should set an exchange rate for other countries' currencies, that is, the exchange rate.