Great question you have there, @PS5844.

I'll share some insights about importing data to QuickBooks Online (QBO).

Yes, you got it correct. When importing data to QBO, it'll only copy the data from your source file. Thus, you can still re-import your data in case you run into some issue with your first attempt.

Furthermore, you'll want to ensure you've mapped the data correctly to import them seamlessly. You can utilize this article for the complete details: Common questions about importing data to QuickBooks Online.

In case you need to export your data from QBO, please see this resource for guidance: Export Data out of QuickBooks Online.

If there's anything else you need help with importing your data to QBO, please don't hesitate to let me know. I'll be around more than happy to help you. Keep safe!