Domestic Supply by Foreign Supplier

I think he will need to register his establishment under GST...

as there are only 3 concepts applicable to foreigners

1) He Exports the goods to India - Pay Customs duty including ACD

2) Comes to India and supplies imported goods locally as an NRTP

3) Register his local establishment under GST law and compliance to be done accordingly (this is applicable in your case)

Dear Mr Hardik,

The foreign supplier is a Company & has no establishments in India

Should he take a Registration as Casual Tax payer with an Authorized Person in India?

How about the ITC on materials purchased in India & sold in India