10 ILCS 5/19-2
Except as otherwise provided in this Code, any elector as defined in Section 19-1 may by mail or electronically on the website of the appropriate election authority, not more than 90 nor less than 5 days prior to the date of such election, or by personal delivery not more than 90 nor less than one day prior to the date of such election, make application to the county clerk or to the Board of Election Commissioners for an official ballot for the voter's precinct to be voted at such election . Such a ballot shall be delivered to the elector only upon separate application by the elector for each election. Voters who make an application for permanent vote by mail ballot status shall follow the procedures specified in Section 19-3 and may apply year round. Voters whose application for permanent vote by mail status is accepted by the election authority shall remain on the permanent vote by mail list until the voter requests to be removed from permanent vote by mail status, the voter provides notice to the election authority of a change in registration that affects their registration status, or the election authority receives confirmation that the voter has subsequently registered to vote in another election authority jurisdiction. The URL address at which voters may electronically request a vote by mail ballot shall be fixed no later than 90 calendar days before an election and shall not be changed until after the election.
10 ILCS 5/19-2