You must complete a wholesale account application, providing your EIN, and Sales & Use Tax ID. We also require you to fill out a CRT-61 Certificate of Resale from the Illinois Department of Revenue (this is required for all states). Please upload all required documents and pictures of your storefront with your application.
https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/sales/documents/sales/crt-61.pdf