Hello @megha,
In QuickBooks Online, your downloaded transactions are based on the information provided by your bank and the system can't control how they're shared. You can delete the duplicate entry from the list of the categorized transaction by excluding it. I'll show you how.
- Go to Transactions.
- Select Banking.
- Under Categorized, find the transaction in question.
- On the ACTION column, select Undo.
- Select For Review.
- Choose the duplicate entry.
- Click Exclude.
In the same manner, here's an article you can read to learn more about how you can exclude a downloaded transaction: Exclude a Bank Transaction you Downloaded into QuickBooks Online.
Additionally, I've also included this reference helpful with the steps needed once you start balancing your actual bank account and in QuickBooks: How to Reconcile your Accounts so they always Match your Bank and Credit Card Statements?
Don't hesitate to post again here if you have other questions or concerns with QuickBooks tasks and navigations. I'm always around happy to help. Take care and stay safe!