Treat services like a clean catalog
Create clear names for the services customers buy most often, then group occasional charges and add-ons separately. Staff should not need to remember a code or type the full service name for every sale.
Keep price changes visible
When a service price varies, start with the usual amount and edit it during billing with a clear reason. Use discounts separately so the final receipt shows the difference between a changed service price and a promotional reduction.
Give each person the access they need
The owner account should not be shared across the team. Cashiers need billing access, while managers may need catalog and team controls. Individual access also makes it easier to remove someone without changing the password for everyone.
End the day with a review
Check completed bills, payment methods, discounts and unexpectedly popular services. A short daily review is more useful than a complicated report nobody opens.