NDA

You are eligible to join Indian Air Force as an Airman based on your educational qualifications. You may look at IAF website and apply online for selection. You will be called for written test, physical and medical test. You may look at IAF website for more details.

Please elaborate NDA.

You are eligible for airman in IAF.

You will have to appear for NDA exam conducted by UPSC for joining NDA. Indian Navy used to hire Technical officer after 12th without appearing in NDA based on marks but this provision has been discontinued this year. Indian Navy will be hiring technical officer after 12th on the basis of JEE Mains score.

NDA I exams will be held on 23 April and NDA II will be held in the month of September 2017.

UPSC conducts NDA examination twice a year. Exam I is conducted in April and Exam II in September. You are not eligible for September exam as you will not be able to clear your 10+2 exam by Dec end. You are advised to appear in Apr 2018 exam by applying in the month of Jan.

Your question is not clear but if your question is on the benefits after retired from NDA, then the answer is as follows:
All permanent commission officers are entitled for pension and other benefits on completion of 20 years service.

During the training period, you get Rs. 36000 and after training, you get 80 thousand.