dear student

you have to appear for IMU CET exam (Indian Maritime University Common Entrance Test) to join Merchant Navy after 12th standard (PCM)

your eye sight should be normal or glasses up to plus or minus 2.5 may be allowed.

your marital status should be unmarried/single

Atter scoring good marks in exam apply for various colleges. for eg. Tolani Maritime Institute, MANET, AMET

hope this helps

All the best!!!