Paid federal or paid state? Who is sending the notices?
How did you select to pay the taxes owed? Look at a copy of your Filing Instructions for the method of payment.
When you sign onto your online account and land on the Tax Home web page, scroll down and click on Add a state.
This will take you back to the 2018 online tax return.
Click on Tax Tools on the left side of the online program screen. Then click on Print Center. Then click on Print, save or preview this year's return.