SSB means Shasaktra Sima Bal & NDA means is National Defence Academy

Under the NDA --
Navy Forces
Air Forces
Army Forces

SSB - Sashastra Seema Bal is a border guarding force under ministry of home affairs (MHA) govt.of India. Recruitment for SSB is carried out from time to time.

NDA - National Defense Academy Exam held in twice in every year and it is conducted by UPSC (Union Public Service Commission) for recruitment in following wings
Naval wing
Air force wing
Army wing