To get back into your return, see the following
1. In TurboTax Online, sign into your account.
2. Select Tax Home in the left menu.
3. Scroll down to Your tax returns & documents.
4. Select 2018, and then select Add a State (you're not actually adding a state, this just opens the return back up)
You'll enter the estimated tax payments you made by typing "estimated tax payments" into the search box and clicking on the "Jump to" link in the search results.
