To access your current or prior year tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on Download/print return (PDF)
A 2018 tax return can only be printed and mailed, it cannot be e-filed.
Print, sign, date and mail the tax return to the IRS. Include with the mailed return any forms W-2 and 1099 which have taxes withheld. Go to this IRS website for mailing addresses - https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment
There are no penalties for filing a tax return after the due date if filing for a tax refund or there are no taxes owed.