To unlock your iPhone using your voice, you can set up the Voice Control accessibility feature on devices running iOS 14.6 and later. Follow these steps:

  1. Open the Settings app.
  2. Go to Accessibility > Voice Control.
  3. Toggle on Voice Control.
  4. Create a Custom Command:
    • Tap Customize Commands > New Command.
    • Type a phrase in the Phrase box that you will use for unlocking.
    • Enable Run Custom Gesture and set a gesture that matches your passcode key entries.
  5. Disable Face ID or Touch ID unlock:
    • Go to Settings > Face/Touch ID & Passcode > Enter your passcode.
    • Toggle off iPhone Unlock.
  6. Lock your iPhone.
  7. Unlock your iPhone using the custom phrase you set:
    • Available on the lock screen when Face ID or Touch ID is disabled.

Please keep in mind that this method may grant anyone who knows your custom phrase unrestricted access to your iPhone, so it's recommended to use this feature sparingly and disable it when not needed.