If you have already filed your tax return, you can still go back in to look around, but please DO NOT change anything in an already submitted return. If you need to change anything you will need to fill out an amended return.
Please the steps below to view your return.
In TurboTax Online, sign into your account.
Select Tax Home in the left menu.
Scroll down to Your tax returns & documents.
Select 2018, and then select Add a State (you're not actually adding a state, this just gets you into the right menu).