Wis. Stat. § 54.47

A certified copy of the petition and order for hearing provided for in ss. 54.34 and 54.38 may be filed in the office of the register of deeds for the county. If a guardian is appointed after a hearing on the petition and if the court’s order includes a finding that the ward may not make contracts, all contracts, except for necessaries at reasonable prices, and all gifts, sales, and transfers of property made by the ward after the filing of a certified copy of the order are void, unless notified by the guardian in writing.