These settings change the label for the discount prompts shown on the quote/order screen.
Click: System Config > Quotations & Pricing > Configuration > Order discounts prompts
Enter free text to add a label to discount 1 prompt and discount 2 prompt, so you can give the 2 discount boxes more descriptive titles.
Tick the box to make the prompts visible on the quote discount window.
Here is the discounts window, in a quote, with 2 customised labels of Discount 1 and Discount 2: