At the end of the bond's term, you then get your original investment back. In the meantime, you can sell your bond on to someone else if you wish. If interest rates generally are going up, the price of the bond will fall. Effectively, this offers new buyers a higher return on their money. Conversely, if rates are falling, bond prices rise, but the holder will still get the same interest income.
Interest rates vary depending on the quality or reliability of the bond issuer.
Government bonds, or gilts, for example, carry little risk and thus offer lower interest rates. Or, in the USA, a stock split. What the accountant says a business is worth. It is calculated by adding retained profits to the initial share capital and is a purely arithmetic calculation. It can be grossly distorted by inflation.