Supply classification under GST clarifies when transactions constitute supply of goods versus supply of services. The Act classifies transactions as supply of goods when title in goods transfers (including future-property-on-payment arrangements) and certain transfers by unincorporated associations, while transfers of rights without title, treatment of another's goods, disposals removing goods from business assets, leases, rentals, construction (subject to completion-linked exceptions), intellectual property use, IT services, agreements to refrain, and transfers of the right to use goods are treated as supply of services; composite supplies like works contracts and provision of food/drink as part of a service are also services.