Wis. Stat. § 59.31

Every writ, notice or other paper required to be delivered to or served on any sheriff may be served by leaving the same at the sheriff’s office during the hours it is required to be kept open; but if there is any person belonging to such office therein, such writ, notice or other paper shall be delivered to such person; and every such service shall be considered equivalent to a personal delivery to or service on such sheriff.