A Demat account, short for dematerialized account, is a digital repository for holding and managing securities in electronic form. It’s an important requirement to trade in the stock market.

A Demat account helps investors hold shares and securities in one place, including:
Stocks, Mutual funds, Bonds, Exchange-traded funds (ETFs), Government securities, Insurance.
A Demat account makes the process of holding investments easier, doing away with the hassles of physical handling and maintenance of paper shares and related documents.
There are two types of Demat accounts:
Repatriable demat account
Linked to a NRE (non-resident external) account that enables money to be transferred abroad
Non-repatriable demat account
Linked to a NRO (non-resident ordinary) account that does not allow transfer of money abroad

A trading account is an online investment account that allows investors to buy and sell securities in the public market. It can also be used to monitor trades.
Here are some features of a trading account:
Buy and sell orders
Investors can place buy and sell orders through a trading platform provided by a broker.
executed trades
The broker executes the trades on behalf of the investor.
Transaction summary
The trading account summarizes the transactions carried out by the investor.
linked to a bank account
A trading account is linked to a bank account through which money can be added to the trading account to buy or sell securities.
Cash and securities holdings
A trading account contains the cash and securities holdings of an investor.
High transaction volumes
Day traders commonly use trading accounts, so they tend to experience high transaction volumes.