Take a look at the following TurboTax article for the steps you need to take to delete a form in TurboTax Online.
If you are trying to delete a Schedule C from a business that was reported on your 2019 return but that is no longer applicable in 2020, take a look at the second article for specific details to follow.
How to view and delete forms in TurboTax Online
How do I delete a prior year Schedule C business that transferred over?