The Tennessee State Government website describes the tax as such:
"If you are a corporation, limited partnership, limited liability company, or business trust chartered, qualified, or registered in Tennessee or doing business in this state, then you must register for and pay franchise and excise taxes. The franchise tax is based on the greater of net worth or the book value of real or tangible personal property owned or used in Tennessee. The excise tax is based on net earnings or income for the tax year."
You'll need to register to file an annual Franchise and Excise Tax return. While Heard doesn't file this tax return for you, this is a more straightforward tax return that you can file on your own each year. You can find the instructions and application to file the return here.