Hello gmills1,
I'm glad to see you dropping by here in the Community. I can assist you with creating discounts in QuickBooks Online.
Right now, the ability to create a line by line discount for the three items on an invoice is unavailable. As a workaround, you can create a discount item from the Products & Service section and add a separate subtotal on each one you create.
Create a Discount account by following these steps:
- Click the Gear icon in the upper-right corner.
- Select Chart of Accounts.
- Click New.
- Below Account Type, select Income.
- Below Detail Type, select Discounts/Refunds Given.
- Enter a name for the discount.
- Click Save and Close.
Once done, please proceed with creating discount item. Here's how:
- Click the Gear icon in the upper-right corner.
- Select Products and Services.
- Click New.
- Select Non-stock or Service.
- Enter a name (example: Discount).
- Below Sales price/rate, enter the discount in a negative amount.
- Below Income account, select the Discount account.
- Remove the check mark next to Inclusive of tax.
Lastly, we can create the invoice and apply discounts to each item:
- Click the Plus sign in the upper-right corner.
- Select Invoice.
- Select a customer.
- Below the Product/Service column, add the item.
- On the second line, add the Discount item.
- Click the Add subtotal button.
- Repeat the same steps for the second and third item.
- Click Save and close.
I'm adding some sample screenshots for your visual guide:


In case you want to give a discount to customers who pay their invoices early, I'm attaching the article I recommend on this:
Set up a discount for early payment.
As always, let me know if you need further help with adding discounts on an invoice. I'll keep an eye out on your response.