CENVAT credit documentation requirement: credit allowed only on prescribed invoices and records, with mandatory returns and dealer safeguards. CENVAT credit is allowable only on prescribed documents-specified invoices, supplementary invoices, bill of entry, or customs appraiser certificates-and is excluded where the invoice indicates credit is not admissible. Missing prescribed particulars may be excused if the document records duty payable, description, assessable value, issuer's Central Excise registration number and premises details and the officer is satisfied goods were received and accounted for. Credit from first or second stage dealers requires dealer records showing duty-paid stock and pro rata duty invoiced; importers issuing invoices are similarly treated. The manufacturer bears the burden of proof and must maintain detailed input records, and specified periodic returns must be filed.