In order to buy or sell share in equity market, you need to open a trading or Demat account. Buying of a company gives the buyer certain rights such as the right to earn dividends and also part-ownership of the company. A Demat account will hold the stocks or shares in your name and the same will reflect in your If you have to buy (long) 100 shares in regular delivery (positional) mode, you need 400*100 = 40,000 rupees, where 100 is the number of shares. In Intraday, approximately the margin needed for this stock is only 20% and then you have to pay 20% of 40,000 rupees, which is 8,000 rupees. Decide how many shares you want purchase, and under what conditions. If you want to buy Microsoft stock today without regard to its current price, you need a market order. If you want to buy only if the price is a certain amount you need a stop or limit order.