Card payment processing is the method by which businesses accept payments made with credit or debit cards. When a customer makes a purchase, their card information is securely transmitted to a payment processor, which verifies the transaction with the card issuer. This process ensures that the funds are available and that the transaction is legitimate. Once the transaction is approved, the payment processor facilitates the transfer of funds from the customer's bank account to the merchant's account. This system allows for quick and efficient transactions, making it easier for customers to pay and for businesses to receive payments.