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.
I assume you are saying that for a married filing jointly tax return, you are listed twice instead of you and your spouse being listed. Did you transfer over any information from last year's tax return for either of you? Was your filing status different last year? If you transferred information from last year from a tax return for only you, you need to list your name first on this year's tax return and enter the other person's name second.
If you do need to clear and start over, use this link to help you: https://ttlc.intuit.com/questions/2586254-using-clear-start-over-in-turbotax-online