To set an alarm on an iPhone, follow these steps:

  1. Open the Clock app on your iPhone.

  2. Tap the "Alarm" tab at the bottom of the screen.

  3. Tap the "+" button in the top-right corner of the screen to create a new alarm.

  4. Use the hour and minute wheels to set the time you want the alarm to go off.

  5. Choose the days you want the alarm to repeat, if any, by tapping on the "Repeat" option.

  6. Tap on the "Sound" option to choose the sound you want to use for the alarm.

  7. Adjust the volume slider to set the volume of the alarm.

  8. Tap "Save" to save the alarm.

Once the alarm is set, it will go off at the specified time, even if your iPhone is locked or in sleep mode. You can turn off the alarm by tapping the "Stop" button on the screen or by pressing the "Volume Up" or "Volume Down" button on the side of your iPhone.