It's a great guidebook if you have any worries about what information you're storing on your iPhone, iPad or Apple Watch.
If you visit the website, you can find out who you're sharing your location services with, and check whether you have two-factor authentication enabled.
The site will also help you figure out whether your face ID or touch ID are enabled.
Check that you're using six-digit passcodes to make sure your phone is safe and secure.
Take advantage of the website here: https://www.apple.com/privacy/control/.