When your iPhone is locked, Siri can perform limited, hands-free tasks like making calls to favorites/recents, sending texts/emails (if enabled), setting alarms/timers, checking the weather, playing music, and answering basic questions, but requires unlocking for sensitive actions like accessing Wallet or reading full messages, with functionality controlled by the "Allow Siri When Locked" setting in Settings > Face ID & Passcode > Siri.
Note that “Hey Siri” works as expected when your device is unlocked. It also works as expected when your device is locked and VoiceOver is disabled.
The only time Siri refuses is when the iPhone is in Airplane Mode with no Wi-Fi calling enabled, because no route to the tower exists. Otherwise, even a locked, stolen, or found phone will connect to 911 through Siri. Dispatchers see the call come in as “911, wireless caller” and can still triangulate the location.
Siri won't read messages, or use any app with private data, with any model iPhone if the phone is locked. It's a security feature, so someone who picks up your phone other than you can't read your messages.
So, imagine you have given your phone to a friend for making a call, but you don't want to really unlock it. But, will your friend still be able to make that call? Turns out they can. Calling from the lockscreen without unlocking your phone is actually a feature on most (if not all) smartphones.
Get personal results on lock screen
Three-finger gestures on iPhone primarily activate accessibility features like VoiceOver (for screen reading and navigation) and Zoom (magnification), allowing scrolling, zooming, and text manipulation (copy/paste/undo) with specific taps and drags, though some text actions work without VoiceOver enabled for quick editing. Common gestures include three-finger double-tap to toggle VoiceOver speech, triple-tap for the screen curtain, and pinching/spreading with three fingers for copy/paste actions, notes this YouTube video.
Say "Hey Siri, lock my phone" if someone grabs it without permission or you need to secure it quickly. The screen locks immediately, requiring Face ID or passcode to access again — even if you're across the room.
However, if you say one thing in particular to Siri, your device will crash. By going to your phone's voice input and saying "hyphen" repeatedly, the device will crash.
Activate your voice assistant – “Hey Siri, call 999” (or “call emergency services”). The iPhone begins a short countdown (usually five seconds), then places the call. You may not speak verbally with the operator, but the line is open and audio is relayed.