Purpose of returns under GST: ensure information flow, verify compliance and finalize taxpayer liabilities while enabling audit and policy decisions. Returns act as the primary information reporting mechanism to the tax administration, enabling compliance verification and matching of input tax credit claims. They facilitate finalization of a taxpayer's liabilities for a given period within limitation timelines, supply data to inform policy decisions, and support the administration's audit management and anti-evasion programs by enabling targeted risk assessment and enforcement.