You either answered a question about having an investment sale or the sale of a home or there was a capital carryover from the 2018 tax return. Clear the return and start over. If you are asked a question that you do not completely understand and there is a Yes/No option select No. You can always go back to any section of the program at any time to enter tax data.
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.