There are many different ways to add a discount. Please note that they are not able to be stacked, the largest discount will be the one that is used.
Click on the item description to see the item details. There you can enter a percentage discount for that specific item and then click Save.
Billable items: Inventory, Procedures, Labs, and Packages
You can edit the billable item and set a percentage discount.
You can also select a category from the list and edit it to set a percentage discount for all items in that category.
A client status can be set up for discounting and then added to any client.
This article goes into details about using the client status for discounts
If you edit the General Information section of the patient medical record you can set a percentage discount
If you edit the General Information section of the client record you can set a percentage discount and the discount type.
When checking out a client you can add a discount and select the discount type