Notifications on iOS appear either as a banner on the top or as alert in a pop-up message. To disable and turn off notifications for apps on iPhone 6, do as follows:
1. Open the Settings application
2. Go to the Notifications settings (on iOS 9, it is the 5th option in the list)
3. Now, under the list of Notification Style, tap the application you want to turn of notifications.
4. Simply make sure the Allow Notifications option is toggled off.
5. You may also specify whether to see the notifications in the Notification Center and Lock Screen or not.