What is the safe area, and how do you keep content clear of the notch, home indicator and keyboard?

The safe area is the part of a view not covered by system chrome: the status bar, Dynamic Island or notch, home indicator, navigation bar and tab bar, plus any extra inset you add. Each view exposes safeAreaInsets and a safeAreaLayoutGuide; a view that is not in a window has zero insets. Pin content to the guide with Auto Layout and it moves out of the way automatically for every device and orientation. A container that already handles its own insets (a scroll view with contentInsetAdjustmentBehavior) takes the values and applies them as content inset. A controller can add its own using additionalSafeAreaInsets, which is how you reserve space for a custom bottom bar without hard-coding a number; the system then adds it to the top and bottom insets.

The keyboard is handled separately, but the modern answer is also a layout guide: pin the bottom of the content to view.keyboardLayoutGuide.topAnchor and it follows the keyboard, including its animation and the floating iPad keyboard, with no notification code. Older code observes UIResponder.keyboardWillChangeFrameNotification and adjusts constraints or insets with the supplied duration and curve. Scroll views and tables inside a controller also adjust automatically in many setups, so test with a field near the bottom. Always lay out against guides, never against the screen size.