A 2018 tax return can be filed using TurboTax at any time for up to three years from the due date.  The 2018 tax return can be e-filed up through October 15, 2019.  After that date the 2018 tax return can only be printed and mailed.

There are no penalties for filing the 2018 tax return after the due date if you are filing for a tax refund or have no taxes owed.