According to Fidelity:
"Merchant Services, or better known as credit card processing is the handling of electronic payment transactions for merchants. Merchant processing activities involve obtaining sales information from the merchant, receiving authorization for the transaction, collecting funds from the bank which issued the credit card, and sending payment to the merchant."
We use a specific processor, Forte Payment Solutions. They are responsible for verifying/processing credit cards and moving payouts in the form of ACH deposits.
For more about merchant processors, check out these links: