How to create a late fee invoice in QB online?

I've got all the steps to help you create a late fee invoice in QuickBooks Online (QBO), David.

It's good news for you because QuickBooks has a feature that automatically calculates late fees on overdue invoices. Once set up, the condition will be applied to future invoices that become overdue and exceed the grace period. They will have an additional late fee item, and their balances will be updated. Here's how to enable the feature:
 

1. Go to the Gear icon and choose Accounts and Settings.
2. Choose Sales and click the Late fees section.
3. Toggle the icon and set the conditions. The instructions are straightforward, but let me know if you have questions.
   
   
    
4. Click Save, and then Done.

Learn more about applying late fees to overdue invoices automatically in QuickBooks Online.

Moreover, if you'd like to manually create and charge a fee to a customer, you can manually create an item for the late fees and add it to the invoice. Here's how:

1. From the Cog Wheel, select Products and services.
2. Tap New, then Service.
3. From the Name field, enter a name for the late fee.
4. Next, from the Category dropdown, choose the category that best describes the fee. Find out more about item categories (Optional).
5. If needed, fill out the rest of the fields.
6. Click Save and close.

Once done, you can now create a new invoice with a new number and select the late fee. For reference, check out this article: Manually add service fees to invoices in QuickBooks Online. 

Additionally, here's an article to learn how to accept electronic customer payments for online invoices and in-person sales.: Take And Process Payments In QuickBooks Online With QuickBooks Payments.

Let me know how I can help you handle late fees further so we can make the most of the feature. Just leave your reply below and I'll be sure to get back.