Stock market has the have all type of investors those are based anywhere like large hedge fund traders, and also small individual investors. The order of that stock traders ends with a stock exchange which involves professional.
Some transactions are done in open outcry means the exchange are physical locations where transactions are carried out on a trading floor, it happens in stock market and commodity exchange her traders enter verbal bids and offers simultaneously.
The other type of stock exchange is a virtual kind, composed of a network of computers where trades are made electronically via traders.
The potential buyer bids a specific price for a stock and a potential seller asks a specific price for the stock. When the bid and ask prices match, a sale takes place on a first come first served basis if there are multiple bidders or askers at a given price.