Aspirants can access previous years' UPSC question papers through various online platforms and official websites. The UPSC website itself archives past exam papers, including those for prelims, mains, and optional subjects. Additionally, coaching institutes and online study portals often provide compilations of these papers along with answer keys. Candidates should also consider joining forums or study groups where members share resources and insights. Accessing these papers not only helps in understanding the exam pattern but also aids in self-assessment and improves preparation strategies.