If the number of invoices in GSTR-1 are less than 500, then GST Portal allows you to manually delete the invoices. Manually deleting these invoices can be very time consuming. If the number of invoices are more than 500, this isn't even an option because GST Portal will not allow you to open that section.
If you or someone else has accidentally uploaded wrong data in GSTR-1, it is always better to start fresh by first cleaning the GSTR-1 data from GST Portal. You can clean the complete GSTR-1 data using Octa GST software in just few clicks.
Open GSTN Tools page: In Octa GST, go to the GSTN Tools page by selecting it in left pane:
Select the GSTR-1 file & Generate: Select the GSTR-1 file downloaded from Govt portal and click on Generate button.
Upload the Cleanup File: Upload the generated clean-up file to GST Portal and all the GSTR-1 data will be deleted in seconds.