To organize an Illinois Limited Liability Company, complete and submit LLC-5.5, Articles of Organization. Starting an Illinois LLC requires appointing a registered agent and submitting your Articles of Organization, along with adhering to annual report obligations.You need to settle on a name, select a business structure, learn about Illinois's tax requirements, and more. Below, you'll find a step-by-step guide. The first thing you will need to do to form an LLC is to complete your Articles of Organization. Then file them with the Secretary of State. This guide outlines the steps necessary to start a business in Illinois, ensuring you are well-prepared to launch your venture successfully. It's fast, easy, and free to get an EINjust fill out Form SS4 and submit it to the IRS. 7. Get up to speed with Business Tax Credits. Forming an LLC in Illinois?