Also keep in mind, that if you have a refund due after completing your 2018 tax return, you will not receive it. The IRS has a 3-year statute of limitations on paying refunds not claimed within three years of the due date of the tax return. Since the 2018 return was due by Apr 18, 2019, you are well past 3 years.
However, on the other side of that coin, if you owe taxes you are still required to pay them, plus interest that started accumulating on the Apr 18, 2019 due date.
