The "Do Not Disturb" feature on an iPhone is located within the Focus settings. Here is how you can find and use it:

• Open the Settings app on your iPhone.
• Tap Focus.
• Select Do Not Disturb from the list of Focus modes.
• From here, you can turn Do Not Disturb on or off, customize who can contact you, set schedules, or enable it based on location or app usage

Alternatively, you can quickly toggle Do Not Disturb on or off via the Control Center:

• Swipe down from the top-right corner of the screen (on iPhone X and later) or swipe up from the bottom (on earlier models) to open Control Center.
• Tap the Focus button (crescent moon icon).
• Tap Do Not Disturb to enable or disable it

When Do Not Disturb is active, a crescent moon icon appears in the status bar and on the Lock Screen

. You can also set Do Not Disturb to activate automatically based on time, location, or while using certain apps by going to Settings > Focus > Do Not Disturb > Turn on Automatically and adding schedules or location triggers

. In summary, "Do Not Disturb" is accessed through the Focus section in Settings or quickly toggled through Control Center on your iPhone.