In the upcoming releases of iOS and macOS, Apple will add a new privacy icon in an attempt to prevent iCloud phishing. It will show up whenever Apple’s apps ask for your personal information. This will help you tell the difference between an official pop-up and a fake one.
Back in October, developer Felix Krause demonstrated that it was easy for a developer to create a fake password prompt. The one he created looked identical to Apple’s official prompt.
You won’t see this icon with every feature since Apple only collects this information when it’s needed to enable features, to secure our services, or to personalize your experience.
In iOS 11.3 and macOS 10.13.4, the Privacy icon will appear at the system level—presumably in the status bar—when Apple asks you to enter your password. If you see the password prompt but don’t see the icon, it should give you a warning that it’s not legitimate.