You will need a brokerage/trading and demat account with Zerodha. Your funds are transferred to your trading account and your stocks & shares will be held in your demat account
If you have a Zerodha trading & demat account, you can login to the smallcase with this link > https://smallcase.zerodha.com/ or from our Android and iOS apps using your Kite credentials
Don't have a Zerodha account?
Read more on Authorization for smallcase here.