You can obtain application form from any Depository Participant (DP) registered with Depository and SEBI. To identify the nearest DP available in your locality, you may obtain the contact details from Depository or SEBI Website (www.sebi.gov.in).
The duly filled application form along with PAN Card and Proff of Address can be submitted to the DP. Any of the following documents is accepted as Proff of Address:
DP may request you to show the original documents for verification at the time of submission of application. You have to enter into an agreement with DP in the standard format, which gives details of rights and duties of investor and DP.
You are entitled to receive a copy of the agreement and schedule of charges for future reference. On furnishing the requisite documents and signing the agreement, DP will open account and give your 16 digit demat account number (8 digit DPID and 8 digit Client ID). This is also called as Beneficial Owner Identification number (BOID). All your purchases / investment in Securities will be added (credited) to this account.
If you sell your securities, your demat account will be reduced (debited). You can have multiple demat accounts if you so wish. You can choose your DP as per your convenience and there is no complusion to open DP account with your stock broker. Broadly, charges are applicable for:-
Source- https://investor.sebi.gov.in/how-do-i.html