Can I claim deductions on investments, insurance etc. purchased after end of financial year?

Hi,

I am a new tax payer and unfortunately I have not been able to acquire investments, insurance etc. which allow me to claim deductions on them during the financial year (due to my busy schedule), so I want to know if I purchase these things after the financial year (i.e after 31st of match), can I claim those under deductions in the assessing year?

Thank you