Place of Supply: determines taxable jurisdiction and whether a supply attracts intra state GST or inter state IGST. Place of supply rules allocate taxable jurisdiction under GST by applying the destination principle: goods are taxed at the location where movement for delivery terminates (or the principal place of business where delivered on a third party's direction) and goods taken on board are supplied at the point of embarkation; services use proxies-location of supplier, recipient, place of performance, place of consumption, or place where benefit flows-with distinct presumptions for B2B (recipient location) and B2C (destination) transactions and sector specific adjustments for immovable property, events, transport, telecom, banking, insurance and brokerage services.