Proof of Ordination
To show you are legally ordained in Wisconsin, you need to show an ordination credential, wallet credential or letter of good standing from the church that ordained you.
Wisconsin Marriage Law
According to Wisconsin state statute 765.16, an officiant is "any ordained member of the clergy of any religious denomination or society who continues to be an ordained member of the clergy," and "any licentiate of a denominational body or an appointee of any bishop serving as the regular member of the clergy of any church of the denomination to which the member of the clergy belongs, if not restrained from so doing by the discipline of the church or denomination."
Where to Become Ordained
There are several online sites where an individual can become ordained to perform marriages in Wisconsin. American Fellowship Church, Universal Life Church, and Open Ministry are all excellent examples of places online that offer services in becoming ordained. They offer information on what functions those ordained by their process can perform in Wisconsin.