Deductions & credits

If you overpaid your 2018 taxes you would have received a refund for the overpayment unless you indicated on your 2018 tax return to apply the overpayment to your 2019 tax return.  TurboTax does not have access to your tax returns so you will have to determine if you applied your 2018 refund to your 2019 tax return,  You can determine if your 2018 refund was applied to your 2019 tax return by looking at line 20a on your 2018 tax return.  If line 20a is blank and line 19 has an amount then the amount on line 19 will be applied to your 2019 tax return

If you have applied your 2018 refund to your 2019 tax return you will report the amount applied from 2018 (2018 tax return line 20a) on your 2019 tax return on Schedule 3 Part II Line 8.