Get a comprehensive understanding of Illinois real estate purchase and sale agreements with our indepth overview and free template. Use a Business Bill of Sale to set out the terms for the sale of a business and transfer the ownership and all assets to the buyer.Step 1 – Fill Out the Buyer and Seller Information. 1. Seller. Write down the seller's full name. Download Illinois Sales Agreement template, modify and send for signing using BoloForms Signature. You (or the purchaser or transferee) must complete Form CBS-1, Notice of Sale, Purchase, or Transfer of Business Assets.