Hi there, @drm53. I appreciate you for seeking assistance with discounts on your invoices. I'm here to help you with setting up a discount per line item.

To get started, please make sure to enable the discount feature from the Accounts and Settings window.

1. Go to the Gear icon, then click on Account and Settings.
2. Tap on Sales at the left pane.
3. In the Sales form content section, click the pencil ✏ icon to edit it.
4. Mark the Discount box. QuickBooks automatically creates a discount account on your register.
5. Hit Save, then Done.

After that, you can create a discount item from the Products and Services.

1. Click on Products and Services from the Gear icon.
2. Tap New to create a new item.
3. Select Non-inventory or Service for the type.
4. Name the item Discount. If you want to create multiple discount items, give them unique names so they're easy to tell apart.
5. In the Sales price/rate field, enter the discount as a negative amount. Keep in mind, this is a dollar amount and not a percentage.
6. From the Income account drop-down menu, select the Discount given account which QuickBooks creates when you turn on the discount feature.
7. From the Sales tax category drop-down, select Nontaxable.
8. Tap on Save and close.

When you're ready, add the item created to your invoices.

1. Open the invoice.
2. Enter another line item for the discount.
3. Click Add subtotal to separate each item and its discount.
4. Click Save and close.

You can also check out this article about applying discounts to the total amount of the invoice: Add a discount to an invoice or sales receipt in QuickBooks Online.

When you're ready to record an invoice payment, you can use this article as your reference: Record invoice payments in QuickBooks Online.

Let me know if you have any other questions about discounts. I'm more than happy to provide additional assistance. Wishing you a good one!