Hi there! thank you so much for responding. I am from Tamilnadu

Please visit the official website at: https://www.tnesevai.tn.gov.in/
Click on Citizen Login and Sign up with an email id and password
Once you sign up and login, you will see an option called "Services" on the left side of the screen.
Click on that and select "Revenue Department" from the drop down list
Click on REV-115 Other Backward Caste Classes Certificate link.
Fill in form accordingly.

priyaankasarkar Thank you so much for the information