Harden your devices against mercenary spyware with Lockdown Mode
Lockdown Mode is an extreme, optional protection for iPhone, iPad and Mac (running iOS 16, iPadOS 16.1 or macOS 13, or later) that should be used only if you believe you may be targeted by a highly sophisticated cyberattack, such as by a private company developing state-sponsored mercenary spyware.
Note: Most people are never targeted by this type of attack.
When a device is in Lockdown Mode, it won’t function as it typically does. Apps, websites and features are strictly limited for security, and some experiences aren’t available. Lockdown Mode includes the following protections:
Messages: Most message attachment types other than images are blocked. Some features, like link previews, are disabled.
Web browsing: Certain complex web technologies, like just-in-time (JIT) JavaScript compilation, are disabled unless the user excludes a trusted site from Lockdown Mode.
Apple services: Incoming invitations and service requests, including FaceTime calls, are blocked if the user has not previously sent the initiator a call or request.
Tethered connections: Connections with a computer or accessory are blocked when the device is locked.
Configuration profiles: Configuration profiles can’t be installed, and the device is unable to enrol into mobile device management (MDM) while Lockdown Mode is turned on. However, any MDM profiles that were enabled prior to Lockdown Mode remain on the device.
Turn Lockdown Mode on or off
Lockdown Mode must be turned on separately for iPhone, iPad and Mac. When you turn on Lockdown Mode on iPhone, it automatically turns on Lockdown Mode for any paired Apple Watch running watchOS 10 or later. You can’t turn Lockdown Mode on or off directly on an Apple Watch.
Do one of the following:
On your iPhone or iPad: Go to Settings
> Privacy & Security > Lockdown Mode, tap Turn On Lockdown Mode, tap Turn On & Restart, then enter your device passcode.On your Mac: Choose Apple menu
> System Settings, Privacy & Security 
> Lockdown Mode, tap Turn On, then enter a password if prompted and tap Turn On & Restart.