Credit cards are financial tools that allow cardholders to make purchases on credit, borrowing money from a financial institution (usually a bank) up to a predetermined credit limit. When a credit card is used to make a purchase, the cardholder is essentially borrowing money from the credit card issuer to complete the transaction. The cardholder is then required to repay the borrowed amount, along with any applicable interest and fees, usually on a monthly basis.

Here are the key features of credit cards:

1. Credit Limit: The credit limit is the maximum amount of money that the cardholder can borrow on the credit card. It is determined by the credit card issuer based on the cardholder's creditworthiness, income, and other factors.

2. Billing Cycle: The billing cycle is the period between credit card statements. During this time, the cardholder can make purchases and use the credit provided by the issuer.

3. Minimum Payment: At the end of each billing cycle, the credit card issuer provides a statement that details the purchases made and the amount owed. The cardholder must make a minimum payment by the due date to keep the account in good standing.

4. Interest Charges: If the cardholder does not pay the full outstanding balance by the due date, the remaining amount incurs interest charges. Credit card interest rates can be relatively high compared to other forms of credit, making it essential to pay off the balance promptly to avoid interest fees.

5. Grace Period: Many credit cards offer a grace period, which is the time between the end of the billing cycle and the due date for the payment. During the grace period, the cardholder can avoid paying interest on new purchases if the previous month's balance was paid in full.

6. Rewards and Benefits: Credit cards often come with rewards and benefits, such as cashback, travel points, discounts, or other incentives. These rewards are offered to encourage card usage and may vary depending on the card type.

7. Fees: Credit cards may have various fees, such as annual fees, late payment fees, foreign transaction fees, and balance transfer fees. Cardholders should be aware of these fees and factor them into their financial planning.

8. Security: Credit cards come with security features, including PIN numbers, EMV chips, and fraud protection, to safeguard against unauthorized use.

9. Credit Score Impact: How a cardholder manages their credit card usage and payments can impact their credit score. Responsible credit card use can help build a positive credit history, while excessive debt or missed payments can harm the credit score.

It's important for credit card users to manage their spending wisely, pay bills on time, and avoid accumulating high levels of debt to maintain a healthy financial profile. Proper credit card usage can provide convenience and flexibility while also contributing to building a good credit history.