Credit cards allow users to make purchases and pay for them later. They are issued by banks and other financial institutions to customers who are deemed creditworthy. When making a purchase with a credit card, the cardholder agrees to pay the issuer back. Issuers charge interest if balances aren't paid in full by the due date. Credit cards come in various types like standard, business, and gold cards. They provide advantages to customers, merchants, and issuers but also carry risks like debt and fraud that require safety precautions.