Bonds are a type of fixed-income security that represent a loan made by an investor to a borrower. When you buy a bond, you are essentially lending money to the issuer of the bond, such as a government or corporation. In return for this loan, the issuer agrees to pay you interest at a specified rate over a defined period of time, and then repay the principal amount when the bond matures.
There are a number of ways to make money with bonds. One way is to simply hold the bond until it matures and collect the interest payments. Another way is to sell the bond before it matures, potentially for a profit if the market value of the bond has increased. Bonds can also be used to generate income through reinvesting the interest payments.