Stocks represent a fractional ownership interest in a corporation. When you purchase a share, you become a partial owner (shareholder) with a claim on the company's assets and potential earnings.
Bonds function as a loan from an investor to a borrower, such as a corporation or government. When you buy a bond, you become a creditor, and the bond certificate. The issuer is legally obligated to pay you a fixed rate of interest (coupon) at regular intervals and return the principal amount (face value) on a specific maturity date.