Estimated taxes are entered under Deductions & Credits > Estimates and Other Taxes Paid. (Click the 1st screenshot below to enlarge it for reference.)
To enter your 2016 estimated tax payments in TurboTax Online:
- Open (continue) your return in TurboTax Online. (If your return isn't open, you'll need to sign in, click Take me to my return, then click Pick up where I left off.)
- Click My Account (top right of your screen).
- Select Tools.
- In the pop-up window, select Topic Search.
- In the search bar, type estimated.
- In the results box, highlight estimated tax paid, then click GO.
- You'll land on the Estimates and Other Income Taxes page. Click Start next to the applicable estimated tax payments you wish to enter, and follow the onscreen instructions. There are options for federal, state, and local estimated taxes. (You can also scroll down to see other options: taxes paid with an extension, 2015 refund applied to 2016, and other income taxes paid in 2016.)
If you made more than the four payments listed on an Estimated Payments page, there is a button you may click to Enter more payments. This will open another screen where you may add your extra payment(s). (To see an example, click the 2nd and 3rd screenshots below.)