10 ILCS 5/20-25
In the event of a deployment of the United States Armed Forces or the declaration of an emergency by the President of the United States or the Governor of Illinois, The Governor or the executive director of the State Board of Elections may modify the registration and voting procedures established by this Article or by rules adopted pursuant to this Article for the duration of the deployment or emergency in order to facilitate vote by mail voting under this Article. The Governor or executive director, as the case may be, then promptly shall notify each election authority of the changes in procedures. Each election authority shall publicize the modifications and shall provide notice of the modifications to each person under its jurisdiction subject to this Article for whom the election authority has contact information.
10 ILCS 5/20-25