A merchant account enables businesses to process online credit and debit payments. Your payment gateway or payment platform deposits the funds aggregated from credit card sales in that account. Based on your agreement with the payment processor, the funds are automatically transferred from your merchant account into your business bank account.
A merchant account is basically a receptacle for deposits. Due to the fact that merchandise sold online may sometimes be returned by the purchaser, you may be required to refund some of the funds, which constitutes a certain level of risk. In order to mitigate risk, returns are subtracted from whatever funds are in the merchant account at the time of the refund, after which the remaining amount is transferred to your bank account.
Payment gateways/platforms, which often collect deposits from a variety of sources, place all of the funds in your merchant account in the form of a single deposit, thereby streamlining payment processes and making reconciliation easier.