Religious organizations should complete Form PTAX-300-R, Application for Religious Property Tax Exemption. The required attachments are listed on that form.The Illinois Department of Revenue will send the applicant a letter approving their property tax exemption application. In this article, we will focus on applying for taxexempt status for 501(c)(3) organizations in Illinois. This includes income, sales, and real estate taxes. If your church or ministry needs a Tax ID, the link to apply online is below. You can also print out and mail a form (Form SS-4). To find out if you qualify, write a letter of request to the Illinois Department of Revenue, Sales. The following forms should be used when registering a charity or professional fund-raising organization with the Illinois Attorney General's Office. Form 1023EZ is used to apply for recognition as a taxexempt organization under Section 501(c)(3).