The Illinois Petition is a legal document used for a variety of cases in the state of Illinois. It can be used to begin a civil lawsuit, to petition for a name change, to file for divorce, or to contest a will or trust. There are different types of Illinois Petition depending on the case. The Petition for Dissolution of Marriage is used to begin a divorce, the Petition to Change Name is used to request a name change, and the Petition to Contest Will is used to challenge the validity of a will or trust. The Petition must be filed in the appropriate court in the county where the petitioner lives, and the petitioner must provide the court with all relevant information about the case.