The first and most reliable source of information is the official government recruitment portal. Here are some popular sites to check for the latest government job vacancies:
Public Service Commissions (PSC) for each state – Websites like www.upsc.gov.in or www.mpsc.gov.in
Union Public Service Commission (UPSC) – www.upsc.gov.in
Staff Selection Commission (SSC) – www.ssc.nic.in
Railway Recruitment Board (RRB) – www.rrbcdg.gov.in