You have to manually allocate most income. W-2 income will usually be allocated by the state name abbreviations shown in box 15 of your W-2. Some states have an allocation form that is submitted with the return. TurboTax will prepare this based on your entries. Here's one example
http://www.tax.ohio.gov/portals/0/forms/ohio_individual/individual/2017/PIT_ITNRC.pdf
