If you are trying to file an extension today, it is too late, an extension needed to be filed by July 15, 2020. If you are due a refund there is no penalty for filing a late return. If you owe taxes, they were due by July 15th to avoid a penalty & interest. You should pay taxes owed as soon as possible.
If you owe taxes, you can pay online on the IRS website for Federal taxes owed, and on your State's website for State taxes owed.