In federal, it says in MA "you can deduct the Motor Vehicle Excise Tax" I've entered registration fees in my federal but don't see where to add Excise in state.

The information you are seeing in the Federal section of your return is trying to tell you that for a Massachusetts resident, the motor vehicle excise tax can be deducted as part of the Federal itemized deductions.  

There is not a separate entry for this amount to be deducted from your state tax return, it is only for the Federal return.

Thank you. This is more clear than I found the language in the entry within TurboTax.