Composite supply rules determine principal supply for GST classification, guiding tax rate application on bundled services. Composite supply under GST follows the concept of naturally bundled services: if elements are naturally bundled in the ordinary course of business the bundle is treated as a single service with the bundle's essential character; if not naturally bundled, the supply is treated as the service attracting the highest tax liability. Assessment uses indicia such as consumer expectation, common market practice, ancillary character of elements, single pricing, package advertising, separate availability, and whether removal of an element changes the supply's nature. The principal supply thus governs classification and tax rate.