Indira Gandhi National Open University 
Maidan Garhi, New Delhi-110 068

Candidates are required to apply online only. 
The Online Link for PhD Entrance Portal is as under :

Important Dates 
 Last date for submission of online application - 23rd March, 2020 
 Entrance Test - 29th April, 2020 
 Declaration of Entrance Result – 8th May, 2020

See link