Turnover threshold triggers audit and submission of audited accounts and reconciliation under annual GST return requirements. Annual return obligations require specified registered persons to file electronically through the Common Portal in prescribed forms: FORM GSTR 9 for most registered persons (with exclusions), FORM GSTR 9A for persons under section 10, and FORM GSTR 9B for e commerce operators collecting tax at source; registrants exceeding the turnover threshold must obtain the statutory audit and submit audited accounts with a certified reconciliation in FORM GSTR 9C.