65. If a document is alleged to be signed or to have been written wholly or in part by any person, the signature or the handwriting of so much of the document as is alleged to be in that person's handwriting must be proved to be in his handwriting.
Bharatiya Sakshya Adhiniyam, 2023
Section 65: Proof of signature and handwriting of person alleged to have signed or written document produced
Chapter V — Of Documentary Evidence
Source: official text of the Bharatiya Sakshya Adhiniyam, 2023 (Ministry of Home Affairs).