The Application Procedure for the Civil Services Examination has been changed to online. The candidates can no longer send postal application forms, instead they are advised to apply Online by using the website: http://www.upsconline.nic.in.
Candidates shall be issued an e-Admission Certificate 3 weeks before the date of examination. The e-Admission Certificate will be available on www.upsc.gov.in for downloading by candidates. No Admission Certificate will be sent by post to the applicants.
There are three options for fee payment for candidates.
NOTE 4 : Candidates should have the scanned images of their photograph and signature # in .jpg format and each photographs should not exceed 40 KB in size and must not be less than 3 KB. That is size for the photograph and 1 KB in size for the signature. Candidates applying online need not send hard copy of the Online Application filled by them online or any other document/certificate/testimonial to the Union Public Service Commission (UPSC). But they should take a printout of the online application, for future communication.
For further details refer: https://www.civilserviceindia.com/civil-services-application-procedure.html