Approved Third Party Software Vendors for Withholding Income Tax (WIT)

If you choose to have a third party file your return, the following are vendors who are approved by the department to electronically file withholding tax returns through the FSET program:

  • AccountantsWorld - Payroll Relief AC
    • Complete payroll processing system designed specifically for professional accountants and payroll processors.
    • Comprehensive system handles every aspect of payroll processing including compliance, electronic payments and more
    • Customizable for businesses with up to 1,000 employees and most industries.
    • Time-saving features that makes payroll processing fast and easy for accountants and employers.
  • Intuit - QuickBooks Payroll
    • Intuit's #1 small business payroll solution.
    • Helps manage payroll more efficiently through an easy-to-use service.
    • Three primary subscription-based solutions range from help with basic payroll essentials to full-service options.
  • Monchilla -
    • Monchilla provides a complete payroll solution that will save you time and money with employee time tracking, paychecks, direct deposit & benefit management.
    • Monchilla lets you e-File federal payroll taxes, W2, 1099 forms, as well as state payroll taxes, including the IL-501 Employer Deposit Statement and the IL-941 Quarterly Reconciliation, Unemployment Insurance UI 3/40 for the state of Illinois.
    • For more information please visit our website at call 1-800-544-3765
  • Quarterly Express Plus Software - developed by Lewis Software Associates, LLC
    • A Windows compatible e-file software product for filing Federal, State, Information and Excise Taxes.
    • This product operates independent of any payroll or accounting systems.
    • A dedicated single point-of-contact in your local area which you know by name and trust.
    • Import your data from a simple Excel or Tab Delimited file for e-filing purposes.
    • You can also manually enter returns and e-file them to Federal or State Agencies.
    • Also provides support for Federal Payroll (941/940/943/944/945), Federal Excise (720/2290/8849), and Affordable Care Act (1094B/1095B/1094C/1095C).
    • You can file your return indirectly or direct to supported state agencies using your own EFIN and Reporting Agent PIN.
    • Contact us at or visit our web site for license information at
  • Paychex -
    • Trusted by over a half million American businesses.
    • Comprehensive, customized solutions for payroll, HR, retirement, and insurance services.
    • Innovative technology and mobility platforms, paired with dedicated, personal service.
    • The preferred provider of payroll, HR, and retirement services by the American Institute of Certified Public Accountants (AICPA).
  • Thomson Reuters CS Professional Suite – Payroll CS 1-800-968-8900
    • Comprehensive and powerful payroll processing system specifically designed for the professional accounting market.
    • Comprehensive calculation capabilities while supporting multiple departments, unlimited pay and deduction items, and multi-state employees and locations.
    • Supports data conversions, data exports, time clock imports, seamless Direct Deposit, federal and state tax form preparation, electronic filing of Forms 940, 941 and 944, and compliance with federally mandated regulations and changes.
    • True integration with other CS Professional Suite Products.
    • For pricing and information, please call a CS Account Representative at (800) 968-8900 or e-mail

For questions regarding this program, please contact the Electronic Commerce Division at 1 866 440-8680.

Note : Some taxpayers are required to pay their tax electronically using Electronic Funds Transfer.