The june 2020 session of IGNOU have not started yet. The official notification will be out around April-May. Keep checking.
You haven't mention in which course you've taken admission, IGNOU has uploaded assignments for July 2019 session to be submitted in March 2020 and January 2020 session for which assignments is to be submitted in Septembet, 2020.
You can get IGNOU assignments by visiting the official website of IGNOU provided below-