The Apple Human Interface Guidelines document Apple's design philosophy across iOS, iPadOS, macOS, watchOS, tvOS, and visionOS, covering everything from color and typography to navigation patterns, gestures, motion, and accessibility.
It's organized into four consistent layers per platform: Foundations (color, typography, layout), Patterns (navigation, onboarding, search), Components (specs for every standard button, tab bar, and alert), and Technologies (platform-specific features like widgets and Live Activities). That structure makes it fast to find the exact spec you need instead of reading a design essay to get one number.
Anyone designing for an Apple platform who needs the actual, current spec (spacing, sizing, gesture behavior) rather than a rough approximation, plus App Store reviewers checking submissions against these standards.
Check the platform tab at the top of each page. A pattern that's correct on iOS often has a different recommended behavior on macOS or visionOS, and it's easy to read the wrong platform's guidance by mistake.
Apple's official guidance for designing iOS applications.
