Can I use a memory stick to import a new QB customer to online QB?

There was a similar question asked some time ago. I think it might help you: https://quickbooks.intuit.com/learn-support/en-us/banking/how-to-import-qbo-file-on-usb-drive-qbb-file-to-new-qbo/00/221291

@brendapenner3-ic 

A memory stick is only a media. The question is what kind of file format do you have? If the file format is QBW, QBB, or QBM, you are able migrating data to QBO easily.

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