1. Set the date and time manually:
   
   Go to Settings.
   Note: The date and time are usually set for you based on your location. Take a look at the Lock screen to see if they're correct.
   
2. Tap General.
   Note: 24-Hour Time may not be available in all areas.
   
3. Tap Date & Time.
   
4. Turn off Set Automatically.
   
5. Set whether iPhone shows 24-hour time or 12-hour time:
   
   Go to Settings.
   
6. Tap General.
   
7. Tap Date & Time.
   
8. Turn 24-Hour Time on or off.