Registration is state-wise
GST is a state-based tax, so you register in each state where you have a place of business making taxable supplies. Each state gives a separate GSTIN (built on your PAN), and each is treated as a distinct taxpayer with its own returns and ITC ledger.
What counts as a presence
You need registration in a state where you have a fixed place of business — an office, branch, warehouse or godown. Merely supplying to customers in another state (without a presence there) does not require registration in that state; you charge IGST from your home state. A warehouse for stock can create a registration requirement — confirm.
A worked example
Example: a company with offices in Maharashtra and Karnataka needs two GSTINs and files two sets of returns. But if it only has an office in Maharashtra and ships goods to Karnataka customers, it stays registered in Maharashtra alone and charges IGST. Opening a warehouse in Karnataka would then trigger registration there. Our team can map your registrations.