All personalized settings on your iPhone are reverted to default values when you reset all settings. Personal data, such as sound, display, and network settings, as well as any custom settings, will remain unaffected. To reset all settings on your new iPhone, follow these steps:

1. From the Home screen, choose Settings.
2. Select General.
3. Restart by pressing the Reset button.
4. Reset All Settings is the last option.
5. Enter the right passcode for your device if required.
6. To finalize the action, choose the option to Reset All Settings.
7. Allow a few minutes for the reset and reboot operations to complete.