Dear Narinder,

JoSSA counselling is a combine counselling to provide admission in IITs/NITs/IIITs and GFTIs.

JEE Main qualified candidates will be eligible for admissions into NITs, IIITs and GFTIs whereas JEE Advanced candidates will be able to apply for admissions into all participating institutes including IIT

Candidates will be able to register themselves for JoSAA 2018 counselling tentatively from the second week of June 2018

To know in detail you can refer below link

https://engineering.careers360.com/articles/josaa-counselling

Good Luck!!