Dear Student,

In JOSSA it is not required but for admission it depends on the authority who is verifying your documents at the time of admission.You should have obc-ncl certificate and income certificate for the safe side because they sometimes ask about family income proof which is necessary at the time of admission or else they can reject your seat so have income certificate for the safe side.It is not mentioned in the documents required if you can make income certificate then it will be good.The documents required for JOSSA are

Provisional JoSAA Seat Allotment Letter 2020

3 passport size photographs

A valid photo Identity Card

Original JEE Advanced Admit Card 2020

Proof of Seat Acceptance fee payment ( the e-challan )

Proof of Date of Birth

Class10th and  12th (or equivalent) Mark Sheet and Certificate

Category Certificate (if needed)

Medical certificate/fitness certificate

Registration form with Locked Choices for Seat Allotment

You can read here the documents required for jossa

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