Complete the worksheet on the back of this page to figure the correct number of allowances you are entitled to claim. Give your completed Form IL-W-4 to your.Complete Form W-4 so that your employer can withhold the correct federal income tax from your pay. Give Form W-4 to your employer. Semi-weekly payments are due three to seven days after every payroll. Gov (search: IT-2104-I) or scan the QR code below. Individuals domiciled in Illinois, Indiana, Kentucky, or Michigan and employed in Wisconsin should file. Every employer who maintains an office or transacts business in Iowa and who is required to withhold federal income tax on any compensation paid to employees.