App Tracking Transparency allows you to choose whether an app can track your activity across other companies’ apps and websites for advertising or sharing with data brokers.
iOS 14.5+ comes with a range of new privacy settings for App Tracking, and you can now ask apps not to track you on your device.
The App Tracking feature is turned off by default, you can verify the status by going to Settings > Privacy > Tracking.
Manage activity tracking permissions
At any time, you can change your mind and give or withdraw permission for an app to track your activity.
Go to Privacy settings to see a list of apps that requested to track your activity. On iPhone, iPad, or iPod touch, go to Settings > Privacy > Tracking. On Apple TV, go to Settings > General > Privacy > Tracking.
Tap to turn off or turn on permission to track for a specific app.
If you turn off "Allow Apps to Request to Track" in privacy settings, you'll stop seeing prompts from apps that want to track your activity. Each app that asks for permission to track while this setting is turned off will be treated as if you tapped Ask App Not to Track. You can also choose to ask all apps that you previously allowed to track to stop tracking your activity. Or you can allow just the apps to which you previously gave permission to continue to track your activity.
More Information: https://support.apple.com/en-us/HT212025