Once you confirm you meet the requirements, you may apply for S Corporation status with the IRS by filing Form 2553. The State of Texas recognizes the federal S Corp election. Your business will still be subject to franchise taxes with the State of Texas.
In general, sole proprietorships and partnerships need to register and file the business name (DBA or assumed name) with their local county clerk's office. If you decide to incorporate, the Secretary of State's Office (SOS) website has information on choosing the right legal structure for you.
Can a Texas LLC operate in another state? Yes. A Texas LLC can operate in another state if it completes the foreign LLC registration process.
In general, what constitutes doing business, or qualifying to do business, ultimately revolves around the ability to sue and be sued. Which is why there is a statutory requirement to maintain a registered agent that resides in Illinois for the sole purpose of accepting service of process and State correspondence.
IDOR registration: In Illinois, most businesses will need to register with the Illinois Department of Revenue (IDOR). IDOR issues Certificates of Registration or License. IDOR also licenses and registers certain retailers and businesses.
Corporation: A Texas corporation is created by filing a certificate of formation with the Texas Secretary of State. The Secretary of State provides a form that meets minimum state law requirements. Online filing of a certificate of formation is provided through SOSDirect.