While you aren’t required to file legal documents to establish a sole proprietorship, if you want to file under a name other than your own legal name you’ll need to pay the $30 for filing a “Registration of Firm Names” form with the County Register of Deeds where your office is/will be located.
Fill out your form completely and properly, getting all required signatures. Then print two copies, one to file and one to have stamped and returned to you for your records.
You’ll then need to get the signature of an authorized person able to administer an oath then officially seal/stamp it. Depending on where you’re having this done, the price can range from about $20-$40 or so for 1 to 2 notarizations.
When the form is completed and you’re absolutely sure everything’s in order, send it off to the local County Register of Deeds. From there, await confirmation of your Wisconsin DBA.
From here you can look into setting up a local business account if you haven’t already, obtaining your EIN or even getting your website off the ground.
Note that this guide’s intent is to provide information on how to file a DBA in Wisconsin, and it should not be in any way treated as a legal document or advice. For more questions on the legalities involved in filing a Wisconsin trade name, consult a business lawyer.