I want to officially welcome you to QuickBooks Online family, rashidaua.
I can help you delete the bank transactions in QuickBooks Online (QBO).
Since you've connected a previous bank account, you can disconnect it and all the transactions in your For Review tab will be deleted.
If you want to delete this account, here's how:
Just a friendly reminder, when you delete an account from QBO:
Take a look at this article for more insights: Disconnect or delete an account.
I'm also including some helpful video tutorials that help with navigating QuickBooks Online: QuickBooks Tutorials.
That should do it. Don't hesitate to reach out to me if you have other concerns. Enjoy your day