65 ILCS 5/7-2-21
In addition to the requirements of the general election law, a distinct ballot shall be printed for each borough for the primary election. At the top of the ballot shall be the following: CANDIDATES FOR NOMINATION FOR MAYOR AND COMMISSIONERS AT LARGE OF THE UNITED CITY OF..... Under the sub-title of FOR MAYOR shall be placed the following: (VOTE FOR ONE). If any commissioner at large is to be nominated there shall be placed below the names of the candidates for mayor another sub-title in the singular or plural form, depending on the facts, the following: FOR COMMISSIONER AT LARGE. Following this sub-title there shall be an instruction in this form, to be altered, however, to conform to the facts. (VOTE FOR ONE). Following the names of the candidates for commissioner at large, if any, there shall be another sub-title in the following form: FOR COMMISSIONER FROM THE BOROUGH OF..... Following this sub-title there shall be the following direction: (VOTE FOR ONE). In other respects the form of the ballot shall be controlled by Section 4-3-10.
65 ILCS 5/7-2-21