The provisions relating to previous conviction or previously convicted person are dealt with in various sections of the Indian Evidence Act and the Criminal Procedure Code (CrPC)
To prove that a person is previously convicted in any civil suit or criminal proceeding, a certified copy of the conviction order must be produced before the court. The certified copy can be obtained from the court that passed the conviction order.
The stage of proof that a person is previously convicted depends on the specific context and purpose of the proof. In a criminal trial, the accused may be asked about his previous convictions at the commencement of the trial. In a civil suit, the proof of previous conviction may be relevant to the credibility of a witness or to the assessment of damages.
It is advisable to consult a legal professional or a court clerk for guidance on the format and procedure for filing such an application or petition.