After civil MBBS how to apply for defence doctor job?

Hello student, 

To join the Indian Army as a doctor, you must study in AFMC.
AFMC stands for Armed Forces Medical College situated in Pune. Earlier, AFMC used to conduct their own exam but not any more. Now, admission is based partly on your NEET Exam.
Eligibility Criteria:
1. He/she must be a Citizen of India.
2. He/she must be unmarried throughout the course.
3. He/she should be medically fit according to the criteria issued by the Ministry of Defence.
4. He/she should have completed 17 years of age but should not be more than 22 years of age (24 years if you're doing a BSc degree and are in final year/have passed).
5. Achievement of atleast 60% in PCB and 50% individually in each subject along with English. Also, he/she should have passed all the subjects in their first attempt. Passing in Mathematics in 10th standard is also required.
Admission Process:
1. When you apply with your NEET result, you are required to take the ToELR test which is a computer based exam testing you in English, Logic and Reasoning. It consists of 40 questions to be done in 30 minutes.
2. The NEET Exam result and the TOELR Exam result are added and divided by 4 to get a score out of 200.
3. An interview worth 50 marks is also held.
4. A merit list is prepared according to the total marks and domicile has no role in it whatsoever.
There are only 105 seats for boys and 25 seats for girls.
You can check out the previous year's cutoffs and other information in the following article:

 http://medicine.careers360.com/articles/afmc-mbbs?amp

Cheers!