Legal Question in Family Law in Illinois

Yes. You must file a Petition for Custody and Removal with the Circuit Court. In that Petition you will also asked for regular child support and a determination of paternity if such has not already been established through the signing of a VAP at the time your children were born. I suggest you contact an attorney in your area immediately to get the ball rolling.

Respectfully, I must disagree. If no case (administrative or judicial) has ever been filed, there is nothing stopping you from leaving. If a case has been filed involving you and the kids, then MS. Roberts-Kurpis is entirely correct.