Since e-filing for the 2018 tax season is closed permanently and forever, you will have to print your return, sign it, and then mail it to the IRS. If you are due a refund, then no late filing penalties will be assessed.
Online tax preparation and e-filing for 2018 returns is now permanently closed. You had until midnight on Tuesday, October 15 to finish and attempt to e-file; if your e-file was rejected you had until October 20 to make corrections and re-file. Now it is too late to use online software or to e-file. If you have any changes/corrections at all to make to your 2018 return, you now have to complete it using desktop software, which you must download to a full PC or Mac (not to a mobile device).
If you already paid for your online software you can ask customer support for a download of the desktop software.
https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number
If you are getting a refund, there is no penalty for filing late. If you owe tax due, then file and pay the amount due as shown on the Form 1040, but expect a bill later from the IRS for the penalty and interest you will owe. Only the IRS will calculate this—TurboTax will not calculate it.