Section 65 BSA — Proof of signature and handwriting of person alleged to have signed or written document produced

The text

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.

Source: India Code (indiacode.gov.in). The Gazette of India is the authoritative text.