iPhone Analytics Data is a feature that collects usage and data information from your iPhone to help Apple improve its products and services. When enabled, this data includes details like your app usage patterns, the frequency with which you use certain features, and general device performance metrics.

To enable iPhone Analytics Data, follow these steps:

1. Open the ‘Settings’ app on your iPhone.
2. Scroll down and tap ‘Privacy’.
3. Scroll down to the bottom and select ‘Analytics & Improvements’.
4. Toggle on ‘Share iPhone & Watch Analytics’. (This might just be called ‘Share iPhone Analytics’ on some iOS versions).

By enabling this feature, you agree to send diagnostic and usage information to Apple. This data is collected anonymously, meaning it isn’t directly associated with your personal identifiable information.

To disable iPhone Analytics Data:

1. Follow the same steps mentioned above to reach the ‘Analytics & Improvements’ section in the Privacy settings.
2. Toggle off ‘Share iPhone & Watch Analytics’.

Disabling this feature means your usage and diagnostic information will not be shared with Apple. However, certain necessary diagnostic data may still be sent as a part of normal device communication with Apple servers.

Most users leave this option enabled because it helps Apple in improving their products, but if you are concerned about privacy or do not want your device’s data being used for these purposes, you might choose to disable it.

Remember that by sharing analytics data, it can also aid in improving overall customer experience by facilitating better app performance and reliability improvements through the aggregation of collected usage patterns.