Hello sanjay,

You should go to official jee main site for registration. The jee mains exam for January session is already ended. The Application of jee mains exam for April session will be released on 7 February 2020 and end on 7 March 2020.

For further details about jee mains, please kindly check below the mentioned link:-

https://engineering.careers360.com/exams/jee-main

I hope this helpful for you.

Best wishes!!