Hi there, emeliechangpanhu.
I can see that you've posted thrice in the Community. My colleague has already answered your concern about uploading a CSV file to QuickBooks Online. To view the thread, check out this link: https://quickbooks.intuit.com/learn-support/en-us/banking/import-missing-transactions-from-excel/01/...
Feel free to comment if you have any other questions aside from importing transactions. We'll be here to help you further. Stay care.