To the extent your minor children receive any money while you are alive, as their parent, you would have authority to manage it for them. If you are worried that you might die while your children are still minors, there are a few things you can do. Probably the best is to create a trust that will receive and manage their assets until they are legally capable of doing so, or even longer; you can set the terms of the trust, including when and under what circumstances distributions are made. The two most common ways of creating a trust for your minor children are to do it in your will or living trust.
Gifts to children can also be made under the Wisconsin Uniform Transfers to Minors Act (UTMA). The custodian of an UTMA account acts as a fiduciary (someone who manages account assets for the child's benefit) and is authorized to collect, hold, manage, and invest a minor's property. Depending on the source of the money that was transferred to your child's UTMA account, your child will assume control of the account from the custodian at age 18 or 21.