The New York Stock Exchange, known as NYSE, is the largest stock exchange in the world (by market capitalization of the companies listed under it). NYSE and other stock exchange is a place where shares of public listed companies are traded. Through this stock exchange, you could place order on the stocks of companies you would like to purchase/sell.
The NYSE is known for listing the stock of traditional blue chip and industrial companies. Companies listed in NYSE includes Coca cola, JP Morgan, Chevron, AT&T, Walmart, etc.