I appreciate the well-detailed information that you've shared, Joe. In QuickBooks Online, custom invoice templates only apply to the invoices created within your QBO account. With this, I can suggest to give us feedback. I'll guide you with the steps.
The custom invoice templates, especially the Default can't be applied when the invoices are imported. Therefore, I'll recommend sending us feedback to help the developers understand the needs and concerns that you encounter. This feedback can lead to improvements in the software and new features that enhance the your overall experience.
Here's how to send us feedback:
- Go to the Gear icon.
- Select Feedback under Profile.
- Enter your comments or product suggestions. Then select Next to submit feedback.
For now, you can manually modify the imported invoices one by one through the steps my colleague, Eduard provided on this thread.
You can also have this article to learn more about customizing invoices in QBO: Customize invoices, estimates, and sales receipts in QuickBooks Online.
Please hit the Reply button if you have any other concerns about importing an invoice into QuickBooks Online.
