Can federal taxes paid in 2019 be deducted from state taxes being filed in 2020?

Most states don't allow a state income deduction for Federal taxes paid....so it depends on what state you are preparing.

For the few that do allow it as a state deduction, that $$ amount will automatically flow from the Federal area to the state forms area, as long ans you fully complete your Federal entries first.

There are six states that allow you to enter the federal tax you paid on your state return--Alabama, Iowa. Louisiana, Missouri, Montana, and Oregon.  If you are filing in one of these states watch for the deduction when you prepare your state return.