I assuming that you are asking for B.tech. 

B.tech addmission in MANIT Bhopal is based on the rank and marks secured by aspirant in JEE Main. ASpirants need to satisfy the eligibility criterias of JEE Main and JoSSA which includes aspects like date of birth, class 12th marks , etc.

Addmission to MANIT involve 2 steps:

1) You need to qualify JEE Mains conducted by NTA.

2) The qualified aspirant need to register and attend the JoSSA counselling for seat allotment. 

You should have atleast 75%(65% for SC & ST) of aggregate marks in Physics , Chemistry and Mathematics.  There is no age limit for JEE Main. JEE Main candidates can appear in the exam for three consecutive years. Since the entrance is conducted twice a year, students can choose to appear in both. However, the attempt for particular year will counted as one.