In addition to completing and dismissing, you can also "cross out" a task:
There are six options to cross out a task. Here's a list of the options, with our recommended options first in the list:
Use the Keyboard Shortcut for crossing out task: Shift-Ctrl-Space. It is the same as the normal hotkey for completing a task (Ctrl-Space) but it adds the Shift key to the mix. This option works on any of macOS, Linux, or Windows.
Hold shift while clicking the checkbox. Pretty self-explanatory: if you hold shift when you click on the checkbox to the left of a task, the task will be crossed out and will remain inline.
Use the task command: !cross-out. All you will really need to press is !cr before "cross-out" will be the default selected option, where you can press enter.
Using the Cross out task button within the task details. You can read more about opening Task Details here. This is usually a slower option than the ones above, but it is available in all of the note modes (as are the other three).
Make tasks get crossed-out by default. You can access this feature in the note menu by navigating through "Triple-dot" -> "More Options..." -> "Manage Tasks." You can turn this feature on and off to have finished tasks crossed out automatically, so you don't have to use keyboard shortcuts or task commands. You must adjust this setting independently for each note.
Swipe tasks to cross-out (Mobile): To display the options to either cross-out or dismiss a task, swipe to the left.
Crossing out a task has the effect of creating a strikethrough bullet item in its place. So, from this:
💪 Work out
to this:
💪 Work out
⚠️ Note that any task properties will be lost by performing this operation. Converting the crossed out task into a normal task will not recover those properties. Pressing command-Z or ctrl-Z (to undo the cross out) will.
With respect to recurring tasks, crossing out works just like completing or dismissing tasks - that is when crossing out a recurring task, a new task will be created for the next occurrence.