Hello, triumphbookkeepe!

I can definitely help you add a discount line item into your invoice.

All you have to do is follow these steps:

1. Click the Gear icon.
2. Select Account and Settings.
3. Click Sales tab.
4. Click the pencil icon under Sales form content.
5. Put a mark into the box next to Discount.
6. Click Save and Done.

If you're using an invoice template, you can edit the template by following the steps below:

1. Click the Gear icon.
2. Select Custom Form Styles.
3. Select the invoice template, and click Edit.
4. Click the Content tab, and then click the pencil icon at the bottom of the invoice.
5. Put a check mark into the box next to Discount.
6. Click Done.

You'll see some screenshots underneath that will walk you through these steps. You can also look at this article for further details: Discounts as line items on invoices

I'm here if you have any more questions about adding a discount line item; feel free to comment down below. Thanks!