How do I clear my tax return for 2019 since I didn’t work

Just because you didn't work in 2019 doesn't mean you don't have to file a tax return. If you had income from other sources, you "could" still be required to file a tax return. (Just be aware of that)

If you have already paid your on-line TurboTax fees, you can not clear your return. Period. End of Story. No further discussion.

Otherwise, under TOOLS on the right you'll find an option to "clear and start over". If that option is greyed out, then you already paid your TurboTax fees and flat out can not clear the return.

What do you need to clear if you didn't enter anything?  If you don't have to file you can just abandon it.  You can try to clear it.

https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-online/00/26444

Do you need to file a return?

https://ttlc.intuit.com/community/filing-and-paying-taxes/help/do-i-need-to-file-a-federal-return-this-year/00/25546