If a customer cannot pay immediately and you want to keep in mind that the customer therefore has an outstanding account, you can use the "on tab" button at the checkout. With the button "on tab" you can checkout at the register when the customer does not have enough money in his pocket or will come to pay later. When this customer visits you and receives treatments again, the outstanding amount will be automatically added to the bill.
This credit is included in the daily receipts when the customer pays (insufficient or not) the first time . It is immediately included in your daily recipe for that day. When the customer later pays the unpaid amount (and the credit is eliminated) it is no longer included in the daily income for this day. This because of the fact that it had been already recorded in the day's reception of the first visit.
The credit is displayed purely for information purposes in the daily receipts on the day it is reimbursed, but is not included again in the total! You can recognize this by the asterisk (*) with your day receptions.