Investments made under Section 80C for the Financial Year 2019-20 could be made up to June 30, 2020. If you made tax-saving investments between April and June 2020, these can be claimed for FY 2019-20, provided you haven't already claimed them for Assessment Year 2020-21.
31 March 2020
You can claim deductions of the tax saving investment made in the period April 2020 to June 2020 for the period FY 2019-20 . The investments made should be in relation to March 2020 or FY 2019-20.