Hello Ritik
The only document which is mandatory for JEE Mains is your Hall Ticket/Admit Card. However, I would also recommend taking some identity proof such as your Aadhar Card just to avoid any issue.
All the best ! 

The invigilators in the exam centre will be very lenient. They will just check your JEE Mains admit card and nothing else. Just don't forget the admit card and your pen/pencil/eraser. 

For the JEE Main exam you need to take the following documents:

• JEE Main 2018 admit card. You will need to download it from https://jeemain.nic.in/webinfo/Public/Home.aspx as there will be no hard copy made available to you
• Your identity card which you have mentioned during the registration (Aadhar Card, Passport etc.)
• PwD candidates must also carry a copy of the PwD certificate in the prescribed format issued by the Competent Authority

Along with these documents be present at the centres before reporting time with a calm mind.

Feel free to ask if you have any more queries. All the best!!