To invest in the stock market, you'll need two types of accounts. To begin, you'll need a trading account where you'll conduct all of your stock market trades. The second is a Demat account, which stores all of your securities in an electronic format.
You cannot have more than one trading account with the same broker under your name. Furthermore, you are unable to add another person to your individual trading account because multiple people are not permitted to access a single trading account.
A shared Demat account, on the other hand, can have up to three holders. However, the account's first holder will get all communication regarding the account. Even a combined Demat account is restricted to a single trading account. As a result, any taxation on the P&L would be the primary/first holder of the shared Demat account's responsibility.