Discounts percentage can be applied individually against the material item when creating a Quote/Sales.
Or in bulk via price levels:
Set up price levels
Bulk update price levels
Have a look at similar frequently asked questions or visit our FAQs page for more information
How do I add admin related notes for a patient?
How can I find a hidden or archived Purchase Order for review?
Can you log time to projects and create schedules with TidyWork?
Do you link to WooCommerce?
How do I add a note to an appointment?