Thank you for visiting the Community space, Priyanka1.
If you have not activated the Multicurrency feature in QuickBooks Online, you can still change your home currency by following these steps:
As for the bank transaction entries that are already added, you'll want to undo them from the Categorised tab. Then, add them again with the correct currency from the For review tab in the Banking page.
On the other hand, if you have the Multicurrency feature enabled, you can only change the home currency by deleting all your data and starting over from scratch.
To learn more about the multicurrency feature and help you categorise the bank transactions, please check out these articles:
Should you have more questions or need help with other task, please let me know in your reply below. I'll be right here to assist you. Take care and stay safe!