Sleep mode on an iPhone is a feature that helps users maintain a regular sleep schedule and eliminate distracting notifications when its time to relax for the evening. When the iPhone is in sleep mode, the screen is dimmed, and notifications are prevented from popping up on the screen. Here are some things that sleep mode does on an iPhone:

• Dimmed screen: When sleep mode is enabled, the iPhone screen is dimmed to reduce the amount of light emitted by the device.

• No notifications: Sleep mode prevents notifications from popping up on the screen, which can help users relax and signal to others that they are unavailable.

• Access to last app: Sleep mode allows users to access the last app they had opened by opening the sleep focus screen, tapping the dismiss button, and swiping up for Face ID or pressing the home button.

• Scheduled activation: Users can schedule their iPhone sleep mode to activate at the bedtime they set via the Health app.

To enable sleep mode on an iPhone, users can go to the Health app, tap Browse at the bottom right, then tap Sleep. From there, they can set up a sleep schedule and enable sleep mode. Users can also customize their sleep focus settings to allow interruptions from people important to them, customize the Lock Screen and Home Screen, and customize how apps and their iPhone behave when a Sleep Focus is on.