Hello dear student

Documents required for JOSSA -

For IIT , ISM -

• Provisional JoSAA Seat Allotment Letter 2020
• Two Passport size photographs
• Candidate Undertaking
• Photo Identity Card (valid)
• Original JEE Advanced Admit Card 2020
• Proof of Seat Acceptance fee payment by e-challan or SBI Net banking
• Date of Birth Proof (10th Standard Mark Sheet)
• Class 12th (or equivalent) Mark Sheet and Pass Certificate
• Medical Certificate
• Category Certificate (if applicable)
• Certificate for PwD (if applicable)
• Passport (for foreign nationals) or OCI Certificate or PIO Card (if applicable)
• DS Certificate (if applicable)
• Registration cum Locked Choices for Seat Allotment.

For IIIT , NIT , GIFT'S -

• Provisional JoSAA Seat Allotment Letter 2020
• Three passport size photographs similar to one uploaded in JEE Main 2020 application form
• Candidate Undertaking
• Proof of Seat Acceptance Fee Payment by e-challan or Internet Banking through SBI
• JEE Main Score Card 2020
• JEE Main Admit Card 2020
• Class 10th Standard Mark Sheet or Date of Birth Proof
• Class 12 (or equivalent) Mark Sheet and Pass Certificate
• Valid photo Identity Card
• Medical Certificate
• Category Certificate (if applicable)
• PwD Certificate (if applicable)
• OCI Certificate or PIO Card (if applicable)
• Registration and Filled Choices for Seat Allotment

Please visit the link for more information about it all information available in details.

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

Hope that's helpful

Best of luck