There are three ways you can add a discount to an order or invoice: 

  1. Add a new line item in the order, called "Discount" and set it as a negative price. 
  2. Adjust the order total to the new price. The only downside with this option is that your client won't see the discount.
  3. Add a "payment" to the order with the "payment type" set to "Credit."

Here's a video that shows each of these three options:

Did this answer your question?