The Apple doesn't switch this feature on by default. While showing advertising that matches the 's interests isn't necessarily a bad thing, there is a risk of that information is being used for other purposes. Private data can also fall into the wrong hands if some advertising company's server is hacked.
In the past few years, Apple has added several privacy-focused features to iOS. The iPhone App Store's Privacy Nutrition Labels inform s about what data each app collects. App Tracking Transparency shows alerts whenever an app requests tracking permission and gives the option to deny apps the ability to freely monitor the 's activity. Despite Apple's efforts to expose profiling and tracking, clever apps and networks can still piece together enough information about the to create a profile.
possible unwanted tracking is the App Privacy Report, which provides details of what data is accessed, such as location, camera, and microphone. Information is also provided about every app's and each website's network activity. A list is collected of the web domains that are ed most frequently. Before the report can be generated, it must be enabled. The can do this easily by opening the Settings app, then scrolling down and tapping the Privacy tab. Scrolling to the bottom of the Privacy section, the App Privacy Report can be found and should be turned on. It takes a while for data to be collected and a few days worth will be more valuable. Apple shows up to the last 7 days of privacy records in this report.
Understanding iPhone's App Privacy Report
The iPhone's App Privacy Report is quite detailed and some parts are easy to understand. The Data and Sensor Access section shows how many times and when an app uses the camera, microphone, and location sensors, as well as accessing s, the photo library, and screen recording. For example, most social media apps need access to the camera to take a picture while in the app. Website Network Activity is fairly straightforward since it's well-known that websites have to access online information and also advertising networks to show ads. What might not be as easy to understand is the App Network Activity. Even though apps are ed to the phone, some are little more than websites wrapped in an app layer. This is particularly true of social media apps and video streaming apps that often perform much the same as the website in Safari.
Perhaps, the most useful part of the App Privacy Report is called Most ed Domains. This summary of domains that might have been ed by multiple websites and apps can use little data in iCloud for convenience so it's safe to ignore these reports. Google provides a large amount of internet infrastructure and that usage is okay, however, Google also sells search engine ads, which is not inherently bad but is something to note. Cloudflare and other CDNs (content distribution networks) smooth out internet traffic by hosting content across multiple servers worldwide. If a suspicious domain is being accessed frequently, an internet search might be able to find out what that domain represents and why an app might be using it. With Apple's App Privacy Report, an iPhone can better monitor whether an app or website might be misbehaving.
Source: Apple