You cannot change the online program to 2018. If you are entering 2018 income to the online software--STOP. Online is only for 2019---no other year. And you cannot combine 2018 and 2019 income on the same tax return. You have TWO tax returns to prepare. Only your 2019 return can be prepared using the online software. Delete any 2018 income you entered into the online program.
Online preparation and e-filing for 2018 is permanently closed.
To file a return for a prior tax year
If you need to prepare a return for 2016, 2017, or 2018 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
If you are getting a refund, there is not a penalty for filing past the deadline. If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.
The current online program can only be used for a 2019 return--no other year. And if you did not file a 2018 return you will have trouble e-filing 2019. When it asks for your 2018 AGI try using zero. If zero does not work then you have to print, sign and mail 2019.
As for your stimulus check---the IRS looks at either your 2018 or 2019 return. Right now they do not have a return from you for either year. Your 2018 return has to be mailed and will take a long time for them to process. Your best bet is to e-file 2019 if you can so they have a return to look at.