A child trust fund is a type of account that your parents or guardians can open for you when you're born. When you turn 18, you can use the money in the account to help pay for things like college, buying a car, or other big expenses. The money in the account is yours and you don't have to pay taxes on it. Your parents or guardians can add money to your account each year, or you can add money to it as you get older.