UIN holders must file GSTR-11 reporting inward supplies and claiming refunds; table 3 populated from supplier GSTR-1. Form GSTR-11 requires UIN holders to report inward supplies and claim refunds, listing UIN, name, supplier GSTIN, invoice/debit/credit note details, taxable values and segregated tax heads. Table 3 is auto-populated from suppliers' GSTR-1 and cannot be edited by the UIN holder. Filing is quarterly or as directed, and the return must include bank details and a verified declaration by an authorised signatory.