Wis. Stat. § 765.19: Delivery and filing of marriage document.

The marriage document, legibly and completely filled out with unfading black ink, shall be returned by the officiating person, or, in the case of a marriage ceremony performed without an officiating person, then by the parties to the marriage contract, or either of them, to the register of deeds of any county in this state within 3 days after the date of the marriage.