Happy to help, @PM219.
I have an easy step to help you scan the back order items onto the same bill. Thus, your inventory reports and transaction will always be accurate.
You'll need to re-open the bill and attach the file using a QuickBooks-Scan Manager. Let me show you how:
If you received an error such as could not scan, 281, or 1, follow this link to troubleshoot it: QuickBooks Scan Manager: Scan and attach documents to transactions.
Did you know that you can snap and attach documents to QuickBooks Desktop Plus or Enterprise 2022 with the mobile app? For more details, see this article: Attach documents to transactions in QuickBooks Desktop.
Moreover, browse these articles if you want to know more about FIFO (First In, First Out), warehouse management, barcode scanning, cost tracking, and more:
If you require additional help, feel free to mention my name in the comment box. I'll reply to you as soon as I can. Keep safe.