You can find and enable the Do Not Disturb feature on your iPhone in the following way:

How to Find and Turn On Do Not Disturb on iPhone

• Using Control Center:
  • On iPhone X or later, swipe down from the top-right corner of the screen.
  • On older iPhones, swipe up from the bottom of the screen.
  • Tap the Focus button (it looks like a crescent moon).
  • Tap Do Not Disturb to turn it on or off. When active, a crescent moon icon appears in the status bar

• Using Settings:
  • Open the Settings app.
  • Tap Focus.
  • Select Do Not Disturb from the list.
  • Here you can customize settings, schedule times, or set location-based activation for Do Not Disturb

Additional Features

• You can schedule Do Not Disturb to turn on automatically at certain times or locations.
• To activate Do Not Disturb until you leave a specific location:
  • Make sure Location Services are enabled (Settings > Privacy & Security > Location Services).
  • Open Control Center, tap and hold the Focus icon.
  • Tap the three dots next to Do Not Disturb.
  • Select Until I leave this location

This setup allows you to silence calls, texts, and notifications during important times or places without disabling location services on your iPhone