If there is no state tax withheld in box 12, then leave all boxes 12-14 blank. If there is box 12 withholding then box 13 must have the state ID and issuers tax ID number.
Box 14 would be blank unless there was tax withheld for two states, then box 14 would show the amount of box 1or 2a that was taxable in each state. If only one state then a blank box 14 indicates that the box 1 or 2a amount applies
Please feel free to post any additional details or questions in the comment section.
