Hello there, @edlane9205.
I'd be glad to help convert your QuickBooks successfully.
Before converting your company file, you may need to determine if your system meet all the requirements and if QuickBooks Online (QBO) is the right fit for your business.
Yes, you can use your flash drive when converting to QBO. However, you may also consider these articles for additional information/reference about converting QuickBooks Desktop file to QBO.
As always, don't hesitate to add a comment below if you have any other concerns about converting QuickBooks. I'm always here to help!