It's nice to have you here, r-goodrum.

You can the Discount Percent or Value feature to apply early payment discounts to your customers. Since discounts are not yet automatically calculated, you'll need to manually apply it on your invoices.

Before that, we'll want to turn on the Discount feature from the Account and Settings page. I'll show you how below:

1. Click the Gear icon.
2. Select Account and Settings.
   
3. From the left menu, select Sales.
4. In the Sales from content section, click the pencil icon to edit.
5. Put a check mark in the Discount checkbox.
   
6. Click Save, then Done.

Once done, you can then apply it on the invoice. When your customer pays early, you can go back to the invoice and apply the discount to zero out the balance.

Here's how:

1. Go to the Sales menu, then choose the Invoices tab.
2. Locate the invoice that was already paid but with a remaining balance.
3. On the lower right of the invoice, click Discount Percent (value).
4. Enter the early payment discount amount, then Save and Close.
   

You can also visit this guide about adding discounts to invoices in QuickBooks Online (QBO): Add a discount to an invoice or sales receipt in QuickBooks Online.

Feel free to comment below if you have further questions. I would appreciate the opportunity to help you with your concerns.