By investing in stocks of a certain company the investor buys an ownership stake in the company. It offers them a sense of belonging to the company you enjoy.
It implies that as a shareholder, they have a say in how a corporation makes choices and can vote on those decisions. Several times, shareholders have intervened to prevent management from making irrational actions that are harmful to their interests.
The annual report of any company is sent to its stockholders to let them know about the functioning.