All Ways to Join Army, Air Force & Navy After 12th in 2023 The NDA and NA Examination is Conducted by the Union Public Service Commission (UPSC) twice in a year. The Full Form of NDA/NA  is National Defence Academy and Naval Academy Wherein Qualified Candidates are Selected for the Defence Services like Indian Army,Indian Navy and Indian Airforce. Candidates must go through the Eligibility Criteria by Visiting the Official Website of UPSC before filling the Application Form .Candidates are required to read all the related Details below for  NDA Eligibility Criteria, Exam Dates , Pattern and NDA Syllabus . How