Accounts and records requirement mandates detailed maintenance, permitted electronic storage, audit obligations and tax assessment for unaccounted supplies. The section mandates registered persons to keep accurate accounts at the principal place of business covering production, inward and outward supplies, stock, input tax credit and output tax, permitting prescribed electronic records and requiring storage-operators and transporters to maintain consignment records. The Commissioner may require additional documents or permit alternate recordkeeping for specified classes. A prescribed turnover threshold necessitates an audit by a chartered or cost accountant and submission of audited accounts and reconciliation; failure to account triggers assessment of tax on unaccounted supplies with statutory tax demand procedures applied.