How to Delete invoice which was raised 2 month before please let me know

It's good to see you posting in the Community forum, @sarveshwar.

I'm here to lend a hand in deleting your invoice in QuickBooks Online (QBO). But before doing so, let me share information with you on the impact when deleting an invoice. 

Once you delete an invoice, you permanently removed it from your company file. On the other hand, if you void an invoice, the system will keep the invoice number and list it in reports but changes the amounts to zero. Thus, if you want to not record the invoice on your books, here's what you'll need to do to delete it:

1. In the left menu, click Sales. 
2. Go to the Invoices tab.
3. Locate and select the invoice you want to delete to open.
4. Click the More button at the bottom.
5. Select Delete.
6. Click Yes to confirm.

For more details about this process, see this article: Void or delete transactions in QuickBooks Online.

Come back to me here if there's anything else you need with your transactions in QuickBooks. I'm always right here to help you. Have a great day.