Merchant navy officers are employed by commercial shipping companies to work on all kinds of seagoing vessels, such as cruise liners, cargo ships, tankers and hovercraft. In order to get admission in Merchant Navy you can apply the entrance exams like IMU CET conducted by Indian Maritime University, CUSAT CAT etc. for Merchant Navy. You can check the eligibility of the exams with given below links.

https://engineering.careers360.com/articles/imu-cet

https://engineering.careers360.com/articles/cusat-cat-eligibility-criteria

Top institute for Merchant Navy are:
Marine Engineering and Research Institute, MERI Kolkata
Marine Engineering and Research Institute, MERI Mumbai
Lal Bahadur Shastri College of Advanced Maritime Studies and Research, Mumbai
T.S. Chanakya, Mumbai
National Maritime Academy, Chennai
Indian Institute of Port Management, Kolkata


Good Luck!