Learn how to complete a marriage affidavit template with our stepbystep guide for newlyweds. The Supreme Court Commission on Access to Justice has approved the following forms.All Illinois Courts must accept these forms. Draft Affidavit: Write the affidavit, including spouses' names, birth dates, marriage date, location, and witness details. A copy of a non-expired, government issued photo ID of the person requesting the correction. • Documentation required to complete the correction requested. Use this form to swear under oath in writing to facts that you personally know. A Marriage Affidavit is a sworn statement affirming the date and validity of a marriage. How do I fill this out? How Do You Write an Affidavit of Marriage?