The steps involved in filing applications for UPSC examinations include initial registration, filling the application form, and paying the prescribed fee. Candidates must first visit the official UPSC website and register using their details. After obtaining registration credentials, they fill in personal and academic information in the application form. It is crucial to ensure all information is accurate and to upload required documents. Finally, after reviewing the form, candidates finalize the process by submitting the application and paying the fee, adhering to submission deadlines to avoid discrepancies.