In order to delete a label, tap the Label List icon [ button_list ] and long-press the label (Android) or swipe the label to the left (iOS). A pop-up window will appear asking you to confirm the deletion.

With tasks it’s similar, just long-press the task (Android) or swipe any task to the left (iOS) and it will be deleted.

Web app:

Even simpler, just use your mouse to hover over a task or a label and select the trashcan icon [ delete ].

NOTE: There are two types of shared labels: Read-only [ readonly_mini ] and Editable [ editable_mini ]. Read-only labels can only be edited and deleted by the person who created them. Editable labels can be edited and deleted by anyone the label is shared to. In order to view your shared labels, select the Shared Labels icon [ share ] (Web & Tablet), or tap the TaskLabels logo [ PM_logo ] and select Shared Labels (mobile).