Shareholders (or "stockholders," the terms are by and large interchangeable) are the ultimate owners of a corporation. They have the right to elect directors, vote on major corporate actions (such as mergers) and share in the profits of the corporation. However, shareholders do not have the right to direct the day-to-day operations of the corporation.
A corporation is required to hold annual meetings of shareholders to elect directors. The minutes of these meetings must be carefully maintained by the corporation. If the corporation has only one or a few shareholders, it may make sense to hold the meetings by conference call, or simply by having the shareholders sign a statement indicating what actions were approved.