If you want to become a captain in Indian Army service/ Indian Navy then you have to do the following things for achieving this post:

1. You are required to clear your 12th class with physics chemistry and mathematics is compulsory subjects.
2. You need to to appear for National Defence Academy or CDS or TES or TGC entrance examination.
3. After the completion of training and 2 years service, you can become captain in Indian army service.

Read more about National Defence Academy by clicking on mentioned below link:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://competition.careers360.com/exams/nda/amp&ved=2ahUKEwiXrOCY85n2AhUayTgGHajJCpkQFnoECAcQAQ&usg=AOvVaw2rE--RRTEeWDolGBpNFhOj

Hello!

In order to become a ship captain, please follow these steps:

1. You have to complete your secondary school studies.

2. Then you need a Bachelor’s degree in relevant courses like Marine Engineering etc.

3. You have to take part in extra training.

4. Gain professional experience.

5. Obtain a master's degree in a relevant course.

6. Then you should explore openings for the role of ship's captains.

7. You must apply for full-time jobs.

You can refer to this link for more information:

https://www.careers360.com/courses-certifications/udemy-how-get-your-coast-guard-captains-license-course

Best wishes