In order to get admission in MNNIT Allahabad, You need to appear JEE Main Entrance Exam. As per the eligibility you should have minimum 65% as a General category or you should be in top 20 percentile in class 12th from the respective board.

NIT admission depends on Home state quota/ Other state quota, category and branches. It would be tough to tell you the exact as the cutoff varies every year. As per 2017 for CSE branch  the opening rank was 299 and 899 was the closing rank Sc category other state quota.

Good Luck!