Tax Year Prior to 2020: What is the W2 state withholding

W2 state withholding is the amount that your employer withheld and transmitted to the state for payment of your state taxes.

On the W2, box 15 shows the state and the state ID of the employer, Box 16 shows the state wages and Box 17 shows the state withholding.

What if I have 2 different states amount on my w2 because I didn't change my address. I shouldn't of had taxes taken for state I no longer lived in.  How do I get that state taxes back?

You will need to file a nonresident tax return in the state you no longer live and allocate zero income to that state in order to get your taxes back.