Swiping is the quickest way to act on a task without opening it.
Swipe left: action buttons
Swipe a task to the left to show up to five buttons. By default:
Tasks: Focus, Track time, Add Pledge, Delete
Projects: Edit note, Add Pledge, Delete
Buttons for features you don't use are hidden.
Screenshot to add: A task swiped left with its buttons
Swipe all the way right: one quick action
Swipe a task all the way to the right to do one thing right away. You'll see the name of the action as you swipe. By default:
My Day and lists: Mark done
Master List: Schedule today (swipe again to unschedule)
A message confirms what happened, usually with Undo.
Changing your swipe actions
Open the sidebar and tap Account & Settings.
Tap Swipe Actions. (Or press and hold any swipe button.)
At the top, choose what you're setting up: Tasks, Projects, List tasks or List projects. "List" means tasks and projects in the Master List.
Under Full swipe, pick the action for a full swipe to the right (or None).
Under Swipe buttons, tap actions to add them (up to five). Hold and drag to reorder.
Common choices: Mark done, Schedule, Schedule today, Schedule tomorrow, Unschedule, Snooze, Track time, Set duration, Add Pledge, Edit, Delete. More are under More.
Screenshot to add: The Swipe Actions settings screen
Label groups as swipe actions
If you use label groups, you can make a group a swipe button or your full swipe. Swiping then shows a picker with just the labels from that group. Handy for things like contexts or energy levels.
Other swipes
Swipe a subtask left to delete it.
Swipe a comment left to edit or delete it.
Swipe a reminder on the Reminders screen to delete it.