B.Tech admissions usually takes places on the basis of entrance Exams. Most of the reputed colleges like NITs and IITs consider Joint Entrance Examination (JEE Main 2019) as the eligibility criteria. To get admission in IITs student has to clear both JEE Main 2019 and JEE Advanced 2019.
Some State and Universities organize their own entrance examination for providing admission in B.Tech course.