To dematerialize your physical shares you have to submit the dematerialization request form (DRF) (in triplicate) to your DP duly filled in and signed by all the shareholders, along with share certificate(s) and necessary documents. In case of joint holders of shares, all the signatories will have to sign on the DRF for it to be valid. Remember, that if you are dematerializing in joint names then names in the share certificate and names in the demat account must be in the same order and must exactly match. Before submitting your DRF and defacing your physical share certificates check 2 things.

Firstly, check that the shares of the said company are registered with NSDL or CDSL and available for demat. Secondly, ensure that the physical share certificates are already transferred into your name and your name is mentioned on the share certificate as the registered shareholder with the relevant distinctive numbers and the folio numbers.