Hello there, @vnguy027.

I appreciate you taking the time to reach out to the community. I'm here to help you assign your discounts in QuickBooks online.

By heading to your company settings, set the Track Classes option in the Categories section to One for each transaction row? 

If your Class tracking setting is set to One, QuickBooks Online will automatically assign the "Not Specified" class to each row in the transaction. We'll need to change the settings from One to the entire transaction to allocate the Discount Given to your desired class.

Here’s how:

1. Go to the Gear icon ⚙.
2. Under the Your Company section, select Account and Settings.
3. On the left tab, click Advanced.
4. Under the advanced tab, select Categories, and turn on Track Classes.
5. Under assign classes, there are two options. Click the drop-down arrow ▼ and select One to the entire transaction.
6. Select "Save” and Done.

Feel free to read this article for more information about Classes and Locations in QuickBooks Online.

To add a discount line item to your invoice. Follow these steps below:

1. Click the Gear icon.
2. Select Account and Settings.
3. Click the 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 checkmark 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.

Visit us again in the Community if you have other questions.