E-filing for the tax year 2018 has already closed. You can prepare your 2018 Tax Return using Turbo Tax downloadable desktop (PC or MAC) software!
Be sure to prepare your state return as well, provided you live in a state that has a state income tax.
Also, when you mail in your prepared tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. It's also a good idea to use a mailing service that will track it, such as UPS or certified USPS. This way you will know when the IRS has received the return.
Go here to prepare and e-file your Turbo Tax 2019 Products income tax return.
Apparently starting this year you can now do an Amended 2018 return online. Did you use Turbo Tax Online to file your 2018 return?
how to amend