If you want to file the 2019 tax return now you will have to change the method of payment to pay by check. The software has not yet been updated to the new dates. Or you can wait until the software has been updated.
The extension to pay the taxes owed is automatic if you have 2019 federal taxes owed. The taxes owed do not have to be paid until July 15, 2020
When filing your 2019 tax return select the option to pay the 2019 tax with a check. Then continue and e-file your tax return.
Then on or before July 15, 2020 go to the IRS payment website and use Direct Pay to the pay the taxes owed - https://www.irs.gov/payments
