https://learn.moneysukh.com/questions-you-need-to-ask-before-choosing-a-discount-broker/

To invest in the stock market you need a discount broker or full-service broker to open trading and demat account with them. Because without having the demat account trading or investing in the stock market is not possible for anyone. As these brokers are members of the central depositaries like CDSL and NSDL also SEBI registered entities to open such accounts.