Friend the minimum educational qualification for NDA is Intermediate.
After passing 12th with a recognized university you are eligible.
NDA exam is conducted by UPSC twice in a year (1) NDA-1 and NDA-2
It has some branches Indian Army,Naval Academy and Air Force
If you want to give this exam you should fulfill some condition as:-
You must be Indian
You must be unmarried male candidate
Age between 16.5 to 19
Selection process of NDA exam:-
(1) Written test
(3)Physical fitness test
This exam is conducted in two sitting
(1) Math-300 marks
(2) English,G.K,Science-600 marks