Enable Developer Mode on the iPhone:
- Keep the phone connected by USB. Unlock it and accept Trust This Computer.
- Open Settings → Privacy & Security → Developer Mode (near the bottom). Close and reopen Settings if it was already open.
- Turn on Developer Mode and accept Restart.
- After the restart, unlock the phone, tap Turn On, and enter the passcode on the phone if asked. The passcode never leaves the phone.
PhoneView rechecks automatically. If the option is missing, use Reveal Developer Mode setting and reopen Settings.