Welcome to the Community, creola.
When you encounter unexpected behavior in QuickBooks Online, it's generally recommended to do a general browser troubleshooting. As an initial step, you can press the F5 key on your keyboard to refresh the page.
Once done, you can go back to your invoice to Save and Send it.
If you're still getting the same result, you can access your account via the incognito portal. You can use these shortcut keys depending on the browser you're using:
- Google Chrome: press Ctrl + Shift + N
- Mozilla Firefox: press Ctrl + Shift + P
- Safari: press Command + Shift + N
If you're able to Save and Send the invoice from there, let's clear the browser's cache on your regular web browser or you can press CTRL+Shift and Delete key on your keyboard altogether.
I'm leaving you this write-up: Record invoice payments in QuickBooks Online. It contains information on how to record multiple and partial payments in QuickBooks Online.
I want to ensure you're able to get back to business, so please feel free to let me know how it goes. Cheering you and your business to continued prosperity.