silly doubt

Can you please provide some context.

When talking about retail sales in a shop, for example, all sales are described as "cash sales" as opposed to "credit sales", because you and I, when we buy something in a shop, the shop doesn't offer us credit - we have to pay immediately. Those "cash sales" may be settled in actual physical cash - notes/coins - or by credit/debit card. At the checkout/cash till/cash register/point of sale - there has to be some record of payments by card. Next time you pay on a debit/credit card - or are with someone who pays on a card - whether in a store or at a restaurant, garage, anywhere ... note that two payment confirmations are printed out - one you keep - the other "cash card voucher/receipt" is retained by the seller.