Dear Shailendra,

After class 12th, there are two entry schemes for officer entry in Defence force, NDA (for airforce, army and navy) and TES (Technical Entry scheme) (for army and Navy).

There are two different TES entries,

1. TES Army

 Age: min 16.5 - max 19.5

 Website for application : joinindianarmy.nic.in

 SSB Call: Based on class 12th percentage. (min 70% in PCM)

2. TES Navy (B.Tech Cadet Entry)

 Age: min 16.5 - max 19.5

 Website for application : joinindiannavy.gov.in

 SSB Call: Based on class 12th percentage. (min 70% in PCM combined + 50% in English in class 10th/12th )

Both entries are offered twice a year (June and November), so, in best case you have total of 6 attempts for TES army and 6 for B.tech Cadet entry.