Let's make sure that your data is accurate as possible, ironman67.
If the invoice is not yet marked as paid, you can edit it by following these steps:
Or else, mark the invoice as unpaid so you can edit the information. Here's a sample screenshot for your reference:
You can also check this article to learn more about easy invoicing in QuickBooks Self-Employed.
For additional questions related to invoices, please don't hesitate get back to us. Thanks.