To register a foreign corporation in Illinois, you must file an Application for Authority to Transact Business in Illinois with the Illinois Secretary of State. Transact Business in Illinois, every foreign corporation must file an.Foreign qualification is the process of registering to do business in a state other than the one in which you incorporated. Illinois requires foreign entities doing business here to qualify and register to do business in our state. Yes. Non-U.S. corporations, LLCs, LPs and financial institutions must register with the secretary of state before transacting business in Texas. But remember, if you don't register your business, you could miss out on personal liability protection, legal benefits, and tax benefits. Your LLC has stores, offices, warehouses, or other physical presences in the state.