If you're like most taxpayers, you'll only need to file one state return, usually in your resident state. You might not even have to file a state return at all if you live and work in a state that doesn't collect income tax.
But if you have income from multiple states, own out-of-state property or business interests that produce income, or your employer withheld taxes for the wrong state, you'll probably need to file a nonresident state return in addition to your resident state return.
And if you moved from one state to another, you'll likely have to file part-year returns in multiple states for that year. You might even have to file a nonresident state return if you started working in the other state before you moved or continued working in your former state after the move.
TurboTax handles nonresident and part-year returns and will determine which state return(s) you need to file based on the information you provide in the Personal Info section.