Payment processing refers to the procedure of verifying and authorizing financial transactions. It involves the transfer of funds from one account to another, either through electronic payment methods such as credit cards or debit cards, or through paper-based checks. The process typically includes authentication of the customer's identity, verification of the transaction amount, and confirmation that there are sufficient funds available in the account. Once these steps have been completed, the payment is processed and the merchant receives the funds. Payment processing systems may be managed by banks or third-party providers, and they play a critical role in ensuring secure and efficient transactions for both merchants and customers.