Hi Pankaj!

Congrats on clearing UGC NET JRF! The Eligibility Criteria for Ph.D. Candidates is that you must have completed Masters in the required subject from any recognised University with a 55% aggregate score! Delhi University conducts Entrance Exam followed by an interview for the Admission Process. Since you have cleared UGC NET JRF Exam, you have an exemption! You need not apply for the Entrance Exam and you'll be asked to attend the interview directly. You must register yourself for the Admission Process which is online! Below I have pinned their Offical Website where you can register:

https://phdadmission.du.ac.in/index.php/site/login

Hope this is helpful!

All the best!