Physical signatures on forms and papers are required to convert your physical shares to Demat mode.
You will need to contact the company's Registrar & Transfer Agent (RTA) if you are unable to sign the documents owing to age or health issues. The RTA's contact information can be found on the company's website under the investor relations section.

Every RTA may have its own set of papers and documentation to fill out. To process a Dematerialization request, RTAs often demand medical certificates from a government hospital as well as a thumb impression of the shareholder.