If you already paid the 2018 state taxes owed, then all you need to do is complete the state tax return, sign, date and mail the return to the state. There is no where to enter 2018 state taxes owed and paid on the 2018 tax return. The state has already received the payment.
There is nothing you need to add to the 2018 federal tax return for payment of state taxes since you did not pay those taxes in 2018.
On your federal tax return for tax year 2022 that you file next year you can enter the state taxes paid in 2022 as an itemized deduction on Schedule A of the 2022 federal return.
