ITR 1 for AY 18-19. Last date for filing return is 31.7.2018. After that date penalty u/s 234F is payable. Please note that.
A new section 234F has been inserted by the government in the Income Tax Act. As per this section, an individual would have to pay a fee of up to Rs 10,000 for filing income tax return after the due dates specified in section 139(1) of the Act.