The 2019 program won't come out until December. You use your current 2018 return.
To prepare estimates for next year you start with your current return, but be careful not to change anything. For Online returns, if you can't get back into your return, Click on Add a State to let you back into your retun.
You can just type W4 in the search box at the top of your return , click on Find. Then Click on Jump To and it will take you to the estimated tax payments section. Say no to changing your W-4 and the next screen will start the estimated taxes section.
Or Go to….
Federal Taxes or Personal (Desktop H&B)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button
The 1040ES quarterly estimates are due April 15, 2019, June 17, Sept 16 and Jan 15, 2020. And don't forget your state. Go to the end of the state section, probably under Other Tax Situations
