One plus 3T - Manual (Page 17)

17 | What’s in the Box Device OxygenOS Safety Information
App permissions
Security is a huge focus of OxygenOS. App Permissions allow you to
control what information and permissions your apps can access,
like location, identity, contacts and more. Don’t want a particular app to
bother you with notifications or access your location?
Customize their permissions in the apps page, found under settings.