Control lock screen notifications
If you've set a pattern, PIN or password, you can control which type of notifications show on your lock 
screen and prevent them from revealing private information.
To adjust notifications for all apps:
1. Go to Settings > Apps & notifications > Notifications.
2.
To hide sensitive content on your lock screen, turn Sensitive notifications off  .
You’ll get lock screen notifications for an incoming email or chat, but they won’t include message 
details.
For finer control, leave this on   to allow details, and instead hide sensitive content from specific apps.
3. To change which notifications show on your lock screen (show all, hide notifications from apps you 
silenced, or hide all), touch Notifications on lockscreen.
To hide sensitive content from specific apps:
1. Set lock screen notifications for all apps to Show conversations, default, and silent.
2.
Touch & hold the app icon, then touch   > Notifications.
3. Types of notifications the app sends appear here. For each enabled notification that you want to hide:
a. Touch the name.
b. Touch Advanced > Lock screen > Show sensitive content only when unlocked.
 
Tip: When you turn on Lockdown, notifications won't show on your lock screen.
Other settings : Apps & notifications 153