Your employer will be providing the 2019 W-2 on or before January 31, 2020. You can either leave the tax data on the 2019 that you have entered and when the W-2 received add or change the W-2 tax data you have already entered.
Or clear the return and start over -
If you have not paid for the online edition you are using, have not filed your tax return or registered the Free edition, then you can clear your return and start over. Click on Tax Tools on the left side of the program screen while working on the 2019 online tax return. Click on Clear & Start Over.