Apple now requires apps to get customer permission to track user data across applications owned by different companies. You can define how you use customer data on your app within your Apple developer account.
This guide has been prepared keeping in mind that normally apps built on our platform, only collect data for improving app functionality. If your app is collecting data for other purposes, please disclose it while setting up the privacy policies.
For example: if you are collecting more than the email address of your app user, disclose it while selecting options in “Data Collection” Form. Furthermore, if your app is going to use the data collected for more purposes than simply improving the App Functionality, you must disclose it in the “Email Addresses” Form while setting up the privacy policies in your developer account.