Let's sort this issue out, Jantco.
You may be experiencing some data-related issues. With that, let's perform the verify and rebuild steps to fix it.
To start with, close all open windows. Then, go to the File menu, and select Utilities. Click Verify Data. If the system prompts you with a specific error message, you may search for it on QuickBooks Desktop support site for how to fix it.
If you see Your data has lost integrity, you'll have to rebuild the file. You can check this article for the detailed steps: Rebuild Company File.
From there, create an invoice to see if the same issue persists.
Moreover, if you want to process payments online, you can check this article: Take and process payments online.
I'm always around whenever you have concerns in creating invoices.
