Hi there, employmentconsul.
I'm here to provide information on how to correct the reference number on the payment in QuickBooks Online (QBO).
You can open the payment transactions and edit the reference number from there.
Here's how:
- Click the Sales menu.
- Go to the All Sales section.
- Find the payment transaction. Then, click Edit.

- You'll be routed to the Received Payment page.
- Edit the reference number.
You can also use this page to adjust payments in another way on how to fix a payment applied to the wrong customer invoice.
Please let me know in the comments below if there's anything else I can help you with. Have a good day ahead.