Carry your matriculation or birth certificate for age proof and your graduation degree or provisional certificate. Bring a caste or category certificate in the prescribed format if applicable, a valid photo ID, and recent passport-size photographs. OBC, SC and ST certificates must be in the central government format with non-creamy layer status where applicable. Keep originals plus self-attested photocopies ready before your DAF or interview stage. The exact list is given in the official UPSC notification.