Enabling notes for tasks gives you a collapsable/expandable note area right underneath the task title.
How to add a note to a task
When the notes strategy is on you will see a note icon on the right of the task when hovering over it.
Clicking the note icon expands the task to show a note area underneath the title. Clicking the note icon again collapses/hides the note.
You can add as much text to the note as you like.
Whenever a task has a note that contains text, the note icon is colored.
You can also add a note to a task by using the "--" shortcut that you type in the title while creating a task.
To see if a task has a note, without hovering over it, you can activate the "Notes icon indicator" option by going to ☰ → Settings → Tasks & Projects → Notes icon indicator.
How to format the text in a note
The text in the note can be formatted in a variety of ways. Highlight the text you want to change or use the formatting commands first and then start typing.
To apply a formatting option hold the cmd/ctrl key and press the following letters:
increase size (j)
decrease size (h)