Credit card, also called debit card, is a credit certificate issued by a commercial bank or credit card company to eligible consumers. It is a card with name, expiration date, number and cardholder's name printed on the front, and a magnetic stripe and signature strip on the back. Consumers with credit cards can go to specialized commercial service departments for shopping or spending, and then the bank will settle accounts with merchants and cardholders, and cardholders can overdraw within the prescribed limits.

CustomerService mainly embodies a value oriented to customer satisfaction, which integrates and manages all elements of the customer interface with the preset optimal cost-service combination. Broadly speaking, anything that can improve customer satisfaction belongs to the category of customer service. Customer satisfaction refers to the gap between what the customer actually "perceives" and what he expects.