Cost Audit Report filing requires CRA-4 with XBRL attachments and prescribed company and auditor details. Form CRA-4 mandates electronic filing of the Cost Audit Report and company explanations under section 148(6)/rule 6(6). It requires company identification, financial year details, SRN of cost auditor appointment, Board resolution date, classification of regulated/non regulated activities, full cost auditor/firm particulars, and disclosure of qualifications, reservations or adverse remarks. Filing must include an XBRL converted copy of the signed cost audit report with explanations for every qualification/reservation and a digitally signed declaration by an authorised representative, with notice of penalties for false statement or evidence.