Illinois Legal Aid Online provides a guided interview called an Easy Form that will help you fill out the forms. Tax Application and Affidavit Forms.Once completed, please submit the applicable form(s) below via email or mail to the address provided on the form. Use this form to swear under oath in writing to facts that you personally know. A copy of a non-expired, government issued photo ID of the person requesting the correction. • Documentation required to complete the correction requested. Learn how to fill out an affidavit correctly with this comprehensive guide. Discover the steps, types, and when you might need an affidavit. Verify statements for legal matters and business transactions using our Illinois general affidavit form template. If you have any questions regarding this affidavit, please call Customer Service at (312)747-4747.