Congratulations shivam. 

The documents you need to submit in the college are :

• Privisional JOSAA seat allotment letter of 2019
• passport size photographs as on mains application form
• Candidate undertaking 
• Proof of seat acceptance fee.
• JEE main score card 
• JEE main admit card 
• Class 10th mark sheet or date of birth proof
• Class 12 mark sheet 
• Medical certificate 
• Valid photo identity card 
• Registration and filled choices for seat allotment
• PwD certificate (if applicable)
• Category certificate (if applicable)

Hope it helps. 

Good luck