My last transactions is not getting updated by my total bank balance is getting updated regularly

Glad to have you here in the Community, @preeti.

There are times that the latest transactions get stuck. Let's manually update your bank account to get this fixed and get you back to working order. 

Before we proceed, you'll want to know about the QuickBooks balance and Bank balance in QuickBooks Online (QBO). The QuickBooks balance is the total balance of all bank transactions that you’ve added or matched to QuickBooks. While the bank balance is your bank's actual balance from the last bank feed update. 

Here's how to manually update your bank account:

1. Click Banking from the left menu.
2. Choose the appropriate bank account.
3. Select the Update button.

I'm adding this article for more guidance: What to do if you get a bank error or can't download transactions in QuickBooks Online.

You might also want to read this link to learn how to match and categorise your bank transactions in QBO. 

Should you need any additional assistance while managing your bank transactions, you can leave a comment below. I'll be around to provide further help.