A Will directs how property and life savings are to be distributed upon your death. A Will is the minimum level of planning required in order to avoid intestate succession, which is when the court follows Iowa law to distribute property. Intestate succession could easily result in distributions that do not match your wishes.
For parents with minor children, a Will allows you to designate a guardian to care for your children if both parents were to pass away. It also allows for a trust to be established upon your death, to ensure funds are maintained to care for your children.