From left to right: iPhone SE (1st generation), iPhone 8, and iPhone X and later
On iPhone 6 and later, and on iPhone SE (3rd generation), press the side button to wake your iPhone or put it to sleep. On iPhone SE (1st generation) and earlier, press the top button.
Use the ring/silent switch to mute sounds and alerts.
If the switch shows orange, it means your iPhone is in silent mode and will vibrate for incoming calls or alerts. When in silent mode, the alarms you set in the Clock app will still sound, and calls from Favorite contacts will still ring.
Use the volume up/down buttons to adjust the volume when listening to music, watching videos, or playing games.
When you press the buttons, you'll see the Volume under the indicator. When you're not using other apps, the buttons will adjust the ringer volume and you'll see Ringer under the indicator.
Home button/Touch ID
Use the Home button to unlock your device or make purchases using Touch ID. Press the Home button once to go to the Home screen. Press the Home button twice to bring up the App Switcher.
On iPhone X and later, and on iPhone SE (3rd generation), press and hold the side button and one of the volume buttons to restart your iPhone. On iPhone SE (2nd generation), 8, 7, or 6, press and hold the side button. On iPhone SE (1st generation) and earlier, press and hold the top button.
Press and hold the side button or Home button to use Siri.