In accounting, a cash transaction is any business transaction that involves some form of exchange of money at the moment of the sale. In accounting, the word cash simply means that the transaction has been settled immediately. So it doesn’t have to be a payment involving actual paper currency. A cash transaction can be in cash, but it can also be a payment made via a credit card, a cheque, or even a bank transfer. All of those payment types indicate an immediate settlement of the transaction and are considered cash transactions. (資料來源 )
A good example of this is when a manufacturer provides goods to a wholesaler. The wholesaler may not have to pay for those goods immediately and can instead have some form of credit period. So a sale is made, but no settlement has occurred. So a credit transaction recognises that there is income due, which means there is a monetary impact on the manufacturer and the wholesaler alike — this is a credit transaction. (資料來源 )