820 ILCS 115/3
Every employer shall be required, at least semi-monthly, to pay every employee all wages earned during the semi-monthly pay period. Wages of executive, administrative and professional employees, as defined in the Federal Fair Labor Standards Act of 1939, may be paid once a month. Commissions may be paid once a month. At the request of a person employed by an employment or labor placement agency which, in the ordinary course of business, makes daily wage payments to employees, the agency shall hold the daily wages and make either weekly or semi-monthly payments. Upon the written request of the employee, the wage shall be paid in a single check representing the wages earned during the period, either weekly or semi-monthly, designated by the employee in accordance with Section 4 of this Act. Employment and labor placement agencies that make daily wage payments shall provide written notification to all daily wage payment employees of the right to request weekly or semi-monthly checks. The employer may provide this notice by conspicuously posting the notice at the location where the wages are received by the daily wage employees. Every employer with employees who do not regularly report to a physical workplace, such as employees who work remotely or travel for work, shall also provide the summary and notice by email to its employees or conspicuous posting on the employer's website or intranet site, if such site is regularly used by the employer to communicate work-related information to employees and is able to be regularly accessed by all employees, freely and without interference.
820 ILCS 115/3