Notifications will be sent from the NHS People app via email, push notifications which appear on your phone/tablet and notifications which appear in the notifications section inside the NHS People app.
To stop receiving email notifications you'll need to click the unsubscribe link at the bottom of each email received from the NHS People app.
To stop receiving push notifications on your mobile you will need to access your device settings, find NHS People in your list of apps and tap on it. Tap "Notifications" and then slide the "Allow Notifications" option to off.