Option 1
The discount can be added to a Customer Order by just manually adjusting the price of the line item.
Click onto the relevant line item > click on the Price and change the amount that you are looking to charge the Customer.
For users to have this ability, they must have the User Permission > Override Price.

Please discuss any changes to your User Permissions with your Manager.
For further information on User Permissions, please review our article - What are User Permissions / How to Setup User Permissions
Option 2
Setting up a FEE for discount
You will need to create the relevant FEE for discount and then just add the FEE as a negative quantity to the Customer Order each time you want to offer the Customer a discount.

This will allow you to run reports on this FEE to see how much discount you are giving away.
TIP: For those dealerships with Accounting Integration, we would suggest you:
- set up a new FEE Category and allocate the General Ledger you want to record all the discount to
- then assign that Category to the new Discount FEE
- this will allow discounts to be recorded in your accounting package under the relevant GL.