Hi there, jake-aswani,

Let me guide you through adding a discount per item to an invoice.

First, turn on the discount feature in QuickBooks Online.

1. Click the Gear ⚙ icon at the right top.
2. Select Account and Settings.
3. Go to Sales.
4. In the Sales form content section, click the pencil ✏ icon to edit it.
5. Mark the Discount box.
   
6. QuickBooks automatically creates a discount account on your register.
7. Click Save, then Done.

Second, create a discount item with a fixed price.

This will set a discount for the amount that you can add after each item.

1. Click the Gear ⚙ icon at the right top.
2. Select Products and Services under Lists.
3. Click New.
4. Select Non-inventory or Service for the type.
5. Enter a unique name of the discount.
6. Select a category. This should be the item you are selling and giving a discount.
7. In the Sales price/rate field, enter the discount as a negative amount.
8. From the Income account drop-down menu, select the Discount given account.
9. From the Sales tax category drop-down menu, select Nontaxable.
   
10. Click Save and close.

Lastly, add the items created above to each item.

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 then record the payment once you receive the payment from the customer.

I've also added this article if you need to apply discount to the total amount of the invoice: Add a discount to an invoice or sales receipt in QuickBooks Online. This link provides detailed steps and instructions.

Let me know if there's anything else you need with your invoice and I'll get back to you.