You don't buy a share from the company that issued it.

When you buy a listed share, you're almost always buying it from another investor who is selling \u2014 not from the company itself. The company already sold its shares once, when it first listed. After that, shares just change hands between investors.

On an exchange\u2014 in India, mainly the NSE or BSE. An exchange doesn't buy or sell anything itself; it's the marketplace where buy orders and sell orders are matched against each other.

You don't place an order directly on the exchange, though. You place it through a broker \u2014 the app or platform you signed up with \u2014 which is registered to send orders to the exchange on your behalf.

Roughly, in order:

1. You place a buy order with your broker.
2. Your broker sends it to the exchange.
3. The exchange looks for a matching sell order \u2014 from another investor.
4. When a match is found, the trade executes at an agreed price.
5. The share moves into your Demat account; the seller's moves out of theirs.