E COMMERCE SELLER registration

If your sales are routed through other e-commerce operators like amazon, flipkart etc, then your existing registration itself is sufficient. But if you are doing it through your own e-commerce platform, then you have to obtain e-commerce registration.

If you are going to start a new product/service belonging to a complete different business vertical, but through e-commerce platform owned by others, then you can obtain different GSTIN within same state but it will be a regular registration and not e-commerce GSTIN. 

But if you are going to start an e-commerce platform for showcasing and selling your existing or new product/service as well as outsiders products then you need to obtain e-commerce GSTIN.