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
Does Tidy connect to a Point-of-Sale terminal?
Do you have hot keys?
Can TidyStock manage multiple price tiers?
How do I reset my password?
How do I connect to the Xero Demo Account?