When you receive unwanted notifications from an app, touch & hold the notification, then tap Turn off notifications.
To review all apps and adjust whether they can send notifications:
Do one of the following:




If an app isn't sending notifications but you want it to:


Your phone can receive free alerts to inform you of public safety messages, threats to life and property (like extreme weather), and other emergencies.
When an emergency alert is sent out, 
You can turn most alerts off or on and adjust alert notification settings. Presidential alerts cannot be turned off.