UPSC accepts the OBC (Non-Creamy Layer) certificate in the format given in its notification.
Download the prescribed format from the UPSC website — do not use a random state format.
The certificate must be issued by a competent authority like a Tehsildar or SDM.
For reservation benefit, the certificate should be of the financial year relevant to the exam.
Carry the original plus a copy for document verification after the main exam.