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 permissions out of context.
Turning off certain permissions may result in basic features no longer working as intended.
To turn permissions on or off for installed apps:
From a Home screen, swipe up from the center of the display to access the apps screen.
Navigate: Settings > Apps & notifications.
Tap See all 'xx' apps.
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 ANYWAY.
The image below is an example.