Wis. Stat. § 344.31

Proof of financial responsibility for the future may be furnished by filing with the secretary the written certification of any insurer duly authorized to do business in this state that there is in effect a motor vehicle liability policy for the benefit of the person required to furnish proof of financial responsibility or by transmitting such certification to the secretary by another means approved by the secretary. Such certification shall give the effective date of such motor vehicle liability policy, which date shall be the same as the effective date of the certification and shall certify coverage for any motor vehicle operated by the named insured if the certification is required to be furnished by a vehicle operator or coverage VEHICLES - FINANCIAL RESPONSIBILITY 344.349 for any motor vehicle owned by the named insured if the certification is required to be furnished by a vehicle owner.