The corporate charter specifies how much stock the corporation can issue, or sell. Stockholders have limited liability for corporate debts. The most you can lose is what you have invested. A corporation has separation of ownership and management. Stockholders own the business, but a board of directors, which are elected by the stockholders, appoints corporate officers to manage the business.
Management is then to maximize the firm's value for the stockholders' benefit.
If that isn't enough, then the corporation pays tax on their corporate income, while the stockholders pay taxes on the cash dividends they receive from the corporation. If you think that stinks, then hear this - it is required that corporations be regulated by the government . The corporation pays money so that the government can make sure the the company discloses information in order for the creditors to make informed decisions. This can get expensive, for many corporations. A corporation issues stock certificates in exchange for money.