GSTR-9 is the annual return that consolidates the monthly or quarterly returns filed during a financial year. It summarises outward and inward supplies, tax paid and input tax credit, and is required for regular taxpayers above a notified turnover, with some exemptions.
Where applicable, a reconciliation statement (GSTR-9C) accompanies it for taxpayers above a higher threshold. Clean monthly filing and reconciliation make the annual return far easier to prepare.