Mutual funds are investment vehicles that pool money from many investors to purchase securities like stocks, bonds, and other assets. There are two main types of mutual funds: open-ended funds that can be purchased or sold at any time, and closed-ended funds that have a set maturity date. Funds also differ based on their investment objectives, such as providing capital growth through equities, generating income from fixed income securities, balancing growth and income, or tracking market indices. The document then provides details on various sub-categories of mutual funds based on maturity period and investment objective.