Different cashier systems should add fees in different ways, and you didn't say which system you used.

Our store uses the cashier software of Chineydy Supermarket, and the processing method is as follows:

In the cashier window, in the bar code entry box, enter *, which is the miter key on the keyboard, or multiplication sign, and then press enter. At this time, a window for entering the amount will pop up, where you can enter the cost, total expenses and points (if there are members). Then make sure. Finally, a line will be displayed in the list of goods called "special goods", which means the service charge.

you can count the service charge details and total amount in the sales details later.