This setting is accessible from the web and mobile platforms. Note that turning this off will stop ALL motion events from being recorded for all cameras on the account. Which means if you are using cameras set to Motion Recording, you will not record any footage and only be able to use live view.
For Business accounts that are using cameras on Continuous Recording, you will still be recording footage, but you will have no way to see events taking place in the timeline (dark blue motion event lines are removed). It is not recommended that you use this if you are just trying to turn off push and email notifications for motion events.
If you would like to turn off notifications see our article here. Alternatively you can also setup a notification schedule.