Religious organizations should complete Form PTAX-300-R, Application for Religious Property Tax Exemption. The required attachments are listed on that form.We've created this stepbystep guide on everything you need to know about creating a donation receipt letter for tax purposes. 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. To find out if you qualify, write a letter of request to the Illinois Department of Revenue, Sales. Knowing how to write an in-kind donation letter for your nonprofit means understanding the do's and don'ts. Let's check them out! To apply for tax-exempt status, your organization will need to either complete Form 1023 or Form 1024. The following forms should be used when registering a charity or professional fund-raising organization with the Illinois Attorney General's Office.