Dear Dipak, UPSC is a civil services examination which is conducted by Union Public Service Commission  for the people who wish to join any government civil services including IPS, IRS, IAS, IFS etc. This exam is conducted once a year in offline mode (pen-paper based exam). Exam is conducted in two stages : prelims ( mainly comprises of aptitude) and mains exam ( carries questions based on your UG subjects). To write this exam candidate must age between 21-32 years. To know more, visit here:

https://competition.careers360.com/exams/upsc-civil-services-exam

Thankyou.