Hi dhyan.bisht.

Let me share some details about importing data.

In QuickBooks Online, we can import data such as bank transactions, customers, suppliers, products, invoices, and bills. For the detailed steps, check this link: Common questions about importing data to QuickBooks Online.

Currently, we don't have a direct way of uploading a journal entry. You'll want to use a third-party file importer instead. Visit the Apps to search for one. 

I'll be here if you need more help. Take care!