Income-tax return categorisation prescribes specific ITR forms and mandated electronic filing methods for affected taxpayers. Substitutes rule 12 to prescribe specific ITR forms for distinct taxpayer categories and income types (ITR 1 through ITR 8 and ITR V), exempts those forms from accompanying tax computations or supporting proofs, and sets permitted filing modes: paper, electronic with digital signature, electronic transmission with ITR V verification, and bar coded paper. It mandates electronic filing for entities subject to audit and companies, directs the Director General (Systems) to specify secure procedures and archival standards for electronic filing, and requires earlier years' returns to follow forms applicable to those years.