Go to any Bank and ask for opening a Demat Account opening Form. Fill up the form and submit the same with all the details and documents as are required. Within 2 - 3 days it will be opened. Some bank do it free and some bank do charge for the same to the extent of Rs.1,000/-
IMPORTANCE
By having Demat account you can keep your physical Shares in electronic form and at the same time you can apply to good IPOs and other public issues. You can also see the present market value of your shares on interest.