Best way to calculate discounts on overall amount

Their are so many post in the forum regarding discount,i don’t know which is the right procedure to follow for my kind of setup.I want to discount based on the amounts spent.
The cashier can decide what to give as discount when the customer is making the payment.It can either be 10%,20%,Or even 5% or the total amount.
Ican also decide to give discount of 5USD ,10USD etc It will all depend on how i want to apply it.
In short,i want to discount based on percentage,amount or even item.Will appreciate your views

Easiest way to discount total is probably by using a calculation to apply the discount, one setup for % and the other for value

The use an auto command button, one for % and one for value set so that when you press it a keyoad pops up and you just enter the value and it will deduct that off the total either by % or value depending on the button pressed

Pretty sure there would be a tutorial for this on here

Discount by item seems to be best as an order tag, inhave a setup that also asks for the reason why an item is discounted or price overridden and this is also added as an order tag so we can report on the reasons for discount/price changes

Heres one to read

In facr search discount and filter for tutorials theres quite a few

thanks sir.i will try out