Short answers, pulled from the story.
A person or legal entity becomes a shareholder when their name and other details are entered in the corporation's register of shareholders. This registration marks them as the legal owner of shares within the share capital of a public or private corporation.
Some shareholders acquired their shares in the primary market by subscribing to initial public offerings which provided fresh capital directly to the corporation at launch. Most shareholders however acquire shares later within the secondary market where trading occurs between individuals without providing capital directly to the corporation itself.
In most jurisdictions this relationship follows trust law and remains simple and passive so creditors cannot seize the trust assets held for the real owner. China's Supreme Court rules show a nominee shareholder cannot escape liability for debt collection actions and must use personal funds to meet capital calls if the true owner fails to pay.
Preference shareholders own different instruments known as preferred stock in American markets and receive a fixed rate of dividend paid before any distribution goes to ordinary shareholders. Most preference shareholders do not hold voting rights within the company structure while owners of common stock generally have the right to influence decisions through participation at general meetings.
Shareholders possess specific entitlements including the ability to sell their shares, vote on directors nominated by the board of directors, and propose resolutions themselves. They may sue the company for violations of fiduciary duty owed to them and retain claims to assets remaining after a liquidation event concludes operations.