Learn how to discover hidden apps on iPhone
Your iPhone has a hidden list of apps that track you. The dreaded page shows apps that can track your web activity, giving you more relevant ads.
Each app on your iPhone can give you a unique advertising ID.
This allows the app to follow you online, including your movements in other apps, according to The Sun.
The idea is that by keeping track of your online movements, apps can give you more relevant ads.
But it does mean that you give up privacy - especially if every app is tracking you.
Apple has rolled out a feature for its Safari web browser that prevents websites from doing this.
But you need to check your iPhone's hidden list to detect any apps that may be tracking you, and then block the tracking activity by the apps you have denied access to.