You can find the garnishment statutes in the Illinois Compiled Statutes starting at the section 735 ILCS 5/12-701.
The Illinois Garnishment statute sets out the law regarding the garnishment of a third party such as an employer, insurer or other parties that might hold assets of another. For example, if you get into a car accident and you are sued and a judgment is entered against you, the plaintiff/judgment creditor might file a garnishment against your insurance seeking payment of the judgment from your insurance company.
In other cases, a judgment creditor might garnish your bank to take the money from your accounts.
You can look up the sections of the statute at your local law library or online. There are several websites with the exact language of the statute.