When setting up your phone or accessing any apple apps for the first time, there's a (labeled) data collection icon at the bottom of the screen that you can tou

When setting up your phone or accessing any apple apps for the first time, there's a (labeled) data collection icon at the bottom of the screen that you can touch for information about what data is collected by each app/process. For the apps, this information is also available in the App Store (just like any other app). You can also view any collected system analytics in Settings -> Privacy- > Analytics & Improvements. Seems relatively fair to me.