The action to delete a To Do can be done in either the main To Do section (as shown in screenshots below) and they can also be done on a user's personal To Do screen. The action to delete is only available to Admin users (or users with increased permissions to that area).
When you enter the To Do screen you will see the 3 dots to the right hand side of each To Do item. These 3 dots are used to action the To Do and will show the option to 'Delete task'.
As seen you can select to see 'All To Dos' as admin or with specified access.
You will see a new 'Reasons' box for why you are deleting certain To Dos.
Once deleted you will see the confirmation message top right in green.