For admission to IITs the candidate should satisfy at least one of these two criteria:

He/she is within the category-wise top 20 percentile of successful candidates in his/her respective Class XII (or equivalent) Board examination.

He/she has secured 75% (for GEN or OBC-NCL) or 70% (SC, ST or PwD) of aggregate marks in the Class XII (or equivalent) Board examination.

All The Very Best and Good Luck :)