Well---do you have any proof that you paid the school district tax---your proof would be your own bank/credit card records. You do not say what state you are in, and we cannot see your information. Was it OH? You could prepare the school district form with your state return, but you have to go through extra steps in the software to do that--did you miss doing it? Look at the 2018 state return and worksheets from your return--if you did it you will find the pages for the school district tax. If you did not do it, then you need to pay the 2018 tax now. And do not make the same mistake next time.