Starting with the 2018 tax year, Form IL-941, Illinois Withholding Income Tax Return, is required to be electronically filed. This can be done by using a third-party software vendor (ADP, Paychex, Intuit, etc.) participating in Federal / State Employment Tax (FSET) program. For businesses who process their own payroll, you can register online to use MyTax Illinois to electronically file your return. MyTax Illinois is free and allows your business to register for taxes, file returns, make payments, and manage your tax accounts.
