Subtasks
A subtask sits indented under another task, for the steps of something bigger. Drag a task a little to the right to make it one.

A subtask goes under the task right above it. There’s one level only: a subtask can’t have subtasks of its own.
Make one
On a phone
Hold the task until it lifts, then drag it a little to the right and let go.
Or tap the task, then ⋯ › Demote to a subtask.
On a computer
Drag the task’s ⠿ a little to the right. Or, while you edit it, press Tab.
Or right-click the task › Demote to a subtask.
The first task in a section has nothing above it to go under, so Demote to a subtask is grayed out there.
Turn it back into a task
On a phone
Hold the subtask, then drag it a little to the left. Or tap it, then ⋯ › Promote to a task.
On a computer
Drag its ⠿ a little to the left, or press Shift+Tab while you edit it. Or right-click it › Promote to a task.
How they behave
- Moved: subtasks always go with their task, within the list or to another list.
- Finished: finishing a task leaves its subtasks open. Finish them one by one.
- Deleted: deleting a task keeps its subtasks: they stay in the section as ordinary tasks.
- A subtask moved to another list on its own arrives there as an ordinary task.