Downloaded apps designed for Android 6.0 (Marshmallow) and up only ask for permission the first time you use a feature rather than asking for permission out of context.
Turning off certain permissions may result in basic features no longer working as intended.
From a Home screen, navigate: Apps icon > Settings > App manager.
Tap the appropriate app.
If available, tap Permissions.
Tap any of the available permissions (e.g., Camera, Contacts, Location, etc.) to turn on or off .
If turning off a permission, from the 'If you deny this permission...' prompt, select Cancel or Deny.
The image below is merely an example.