Ensure 'All apps' is selected (upper-left).
If necessary, tap the Dropdown icon then select All.
Locate then select the appropriate app.
If system apps aren't visible, tap the Menu icon (upper-right) > Show system apps.
If available, tap Permissions (App settings section).
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.