Money market funds invest in good quality government guaranteed investments with very short time frames. These investments pay interest to investors. They are most appropriate for short term investment and savings goals or in situations where you want to safeguard the value of your investment while still being paid interest. Money market funds have relatively low risk compared to other mutual funds but they also have low returns. However, they do usually pay higher interest than a savings account or short term deposit.
Bond funds invest primarily in bonds.
When you buy a bond, the company selling it to you is promising to pay you your money back on a certain date with interest. Unlike money market funds, bond funds are not restricted to investments with short time frames. Some bonds come due in 20 years. There are many different kinds of bond funds and as a result they vary in their risks and returns. When you buy a stock of a company you are buying a piece of the ownership of that company.