You'll need a marriage license to get married in Illinois. Both parties need to be present.Fill out and sign a marriage license application. First, parties who intend to marry must go to the County Clerk's office in the county in which they wish to be married to obtain a marriage license. To qualify as an S Corporation in Illinois, a business must first be registered as a corporation in the state. Marriage application must be completed before the couple comes to the office. Please make sure to obtain your marriage license at least 1 day BEFORE your marriage ceremony. Entering Search Criteria. It is necessary for both parties to come in to the office to fill out and sign the marriage license application. The first step to beginning a corporation is filing your articles of incorporation.