Hi there Vihar!
Don here from Shopify!
At the moment, it would only be possible to add gateways from our list of gateways available for use in India with your Shopify store.
We're not currently accepting new gateway provider requests at the moment so it would be necessary to use one of the existing gateway choices visible on that page.
Check out the options there and if you have any other questions you can always reach out to us via our support site. :)
All the best!