It depends you see. If you are applying to Manipal, then you have to have at least 50% in class 12 and appear for MU OET. the Tamilnadu offers it at many colleges through TNEA. Here also minimum 50% is required. Karnataka colleges also offer but other state candidates will not be eligible. However you appear for COMEDK. here minimum 45% is required. If you let me know which state you belong to, we may suggest colleges if any within the state.

Percentage criteria is different from college to college. It's totally depends on in which college you are applying for.

Please mention the name of the college?

If you want to take admission in IITs you should have 75% marks in your board exam or you should be in top 20 percentile. For SC/ST you have to get 65% marks.

Good Luck!!