Companies not claiming exemption under section 11 (charitable or religious purpose) of Income Tax Act, 1961 has to file their return using ITR 6. All companies are mandatorily required to file their return on or before 30th September in order to free from penalty and other consequences. Companies should submit their return electronically using digital signature.
ITR-6 can be downloaded from https://incometaxindiaefiling.gov.in/