I am guessing that you have not entered the amount you paid before the April deadline (was this with your extension), so TurboTax is unaware that you no longer owe the IRS anything but are due a refund. Is this correct?
If you need to add the amount you paid with the extension, then open your return, go to Deductions & Credits, then go down to subheading Estimated and Other Taxes Paid and click on Start (or Revisit) for Income Taxes Paid.
Answer "Yes" on the next screen, then continue to "Payments with 2018 federal extension". However, if you made the payment on a 1040-ES, then you enter this amount on a related screen under the subheading Estimated and Other Taxes Paid.
