The option to do so is not open just yet. TurboTax Easy Extension for e-filing an extension, should be available sometime later today, March 22, 2018. Give it a few more hours, as the developer team that handles that runs on Pacific time, so it's still early their time.
If you do not owe federal taxes on the 2017 tax return there is no reason to request an extension. You can file a tax return at any time if you have no taxes owed or a tax refund without any penalty.
The option to do so is not open just yet. TurboTax Easy Extension for e-filing an extension, should be available sometime later today, March 22, 2018. Give it a few more hours, as the developer team that handles that runs on Pacific time, so it's still early their time.