Sole proprietorships are filed only at the county level. Check with your County Recorder's office to determine filing requirements.Form REG-1, Illinois Business Registration Application, to us at the address on the form (Form REG-1 is available on our web site as a fill-in and savable form. Download a free Illinois LLC Operating Agreement template (Word, Google Doc, PDF). List LLC Members, profit splits, tax info and more. This guide will inform you of various legal requirements and direct you to additional resources. (This form is not required if you currently or previously have held a City of Chicago Business license as a sole proprietor.). ("Contractor"), and the City of Chicago, a municipal. To establish a series LLC, please submit the Articles of Organization Form LLC-. 5.5(S) instead of Form LLC-5.5.