Hey there

If you want to join Indian army after your Engineering then you can go for CDS which is the most famous but in CDS all graduates can apply. TGC is a technical entry and your selection will be based on SSB. You can go for short service commision too. Also if you want to join air force then AFCAT is one of the most famous and it has technical entry.

Check the link

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.careers360.com/careers/career-in-defence-after-engineering/amp&ved=2ahUKEwiAvbyVwpXqAhXQxTgGHamDBqYQFjABegQIDRAI&usg=AOvVaw11s7fdiuE-M6MkuA5BVIM_&ampcf=1

Good luck