Hi

You can apply online for the caste certificate using the following link

https://services.india.gov.in/service/detail/apply-for-other-backward-classes-certificate-in-tamil-nadu (https://services.india.gov.in/service/detail/apply-for-other-backward-classes-certificate-in-tamil-nadu) Once you receive the certificate, you can attach it with your JEE Mains and Advanced application forms, and you will be eligible for caste based benefits.

Hope this helps!