Invoice Cancellation / Deletion on the same moth before filing GST 1R or GST 3B

If you've mistakenly created an invoice before filing your GST returns and haven't issued it to the client, you can simply cancel it. It's not mandatory to issue a credit note in this scenario. You should document the cancellation by printing the invoice and marking it as cancelled before deleting it from your system. Remember to report the cancelled invoice number in the document summary section of your GSTR 1 return.