Org for your e-commerce business covers everything you need to know. In the case of Illinois, which is an origin-based state for sales tax, the key factor is the location of your business, not the customer's shipping address.Where do I register a business? 1st Quarter filing due April 20th! Using MyTax Illinois, you will register a new account indicating general merchandise, wholesale in the business activities section. You are a remote retailer. To organize online, the LLC must meet the following requirements: Limited Liability Company Name The name must include one of the following: The state of Illinois requires marketplaces to collect sales tax on behalf of sellers on online marketplaces like Amazon and Walmart. Get compliant in Illinois. Here's our step-by-step guide to Illinois sales tax registration for e-commerce sellers.