Definition of supply clarifies supplier, input tax credit, place of supply and platform liability for specified actionable claims. Section 2 defines core operative terms: supply and supplier (including deeming of platform organisers for specified actionable claims), input tax and input tax credit (enumerating qualifying taxes and exclusions), and intermediating roles such as 'Input Service Distributor.' It also sets out classification rules for composite and mixed supplies, place and location rules for supplier and recipient, and the scope of registered, taxable and non-resident taxable persons.