Certificate of expenditure for section 35AC projects requires project details, taxpayer identifier, expenditure period and authorised auditor signature. Certificate of expenditure for projects or schemes notified under section 35AC must identify the contributor by PAN, Aadhaar or G.I.R. number, state the expenditure amount (figures and words), specify the notified project with notification number and file reference, record the expenditure period, financial year, estimated project cost and assessment year(s), and be signed and dated by a chartered accountant or a person entitled to act as company auditor.