Stock exchanges provide a platform for buyers and sellers to trade stocks, bonds, and other securities. Companies list their shares on stock exchanges to raise capital from investors. There are various types of traders on stock exchanges, including brokers who execute trades for clients, jobbers who deal directly with brokers, and speculators who take high risks seeking high returns. Regulators like SEBI oversee stock exchanges to promote orderly and fair trade. To invest, one must open a demat account similar to a bank account to enable buying and selling of listed securities.