65 ILCS 5/4-3-7
Any person desiring to become a candidate for nomination for mayor or commissioner shall file with the municipal clerk, or, in those municipalities having a board of election commissioners, with the clerk of that board, a statement of his candidacy, in the form provided in the general election law. This statement shall be filed at the time provided in the general election law.
This statement shall be sworn (or affirmed) before an officer, in which the person making the statement resides, authorized to administer oaths. If the municipality has voted, as provided in Section 4-3-19, to require candidates for commissioner to run for a specific office, a statement of candidacy for commissioner shall specify whether the candidacy is for commissioner of accounts and finances, commissioner of public health and safety, commissioner of streets and public improvements, or commissioner of public property. No person shall file statements of candidacy for both mayor and commissioner or for more than one of the commissioner offices.
Any person having filed as a candidate for mayor or commissioner may withdraw within the time provided in the general election law.
65 ILCS 5/4-3-7