Dear aspirant

Yes, income certificate is not of that much importance during counseling,so you can submit later after joining the college

Although other documents like domicile/resident certificate and caste certificate you should must carry during the counseling process if you are eligible for reservations on basis of category.

Also don't forget to carry other necessary documents which you need, same instructions will be given along with your allotment letter

Hope this information helps you

All the best