Hii aspirants

let me clear your doubt.

To join National Defence Academy a candidate have to appear in the entrance exam conducted by Union Public Service Commission, twice a year, one in month of March and 2nd in the month of August.

Also a candidate should be a unmarried male.

To join NDA one must pass written followed by SSB, medicals and finally to be in merit list.

and for ina

A candidate can get admission in ina after 12 through UPSC NDA examination or TES (10+2 Technical Entry Scheme).

Also if a candidate have PCM in 10+2 can apply for this entry, there will be  no written examination for them. candidates are shortlisted on the basis of a Cut Off in percentage marks.

I hope my answer will help you out

Good luck