Visit the Illinois Secretary of State – Business Services page
https://www.ilsos.gov/departments/business_services/business_searches.html
Locate your entity using the business name or file number.
Download the correct Amendment Form:
● LLC: Form LLC-5.25
● Corporation: Form BCA-10.30 or BCA-10.20
● Nonprofit: Form NFP-105.20
All forms here:
https://www.ilsos.gov/departments/business_services/publications_and_forms.html
Complete the form with updated details.
Submit the form online or by mail with the required filing fee ($50–$75 depending on entity type).
Wait for confirmation from the Illinois Secretary of State (email or mail).

● New business name, address, or ownership changes.
● Updated registered agent (if applicable).