Some features can be used from the Lock Screen without unlocking. If you turn that off, someone holding your iPhone can't see personal information such as an upcoming event in the Calendar widget.
If you leave it
Anyone holding your locked iPhone can use these features and may see personal information.
Where to find it
Settings
Face ID & Passcode
Go through
Step by step
1.
Open Settings and tap Face ID & Passcode. On an iPhone with a Home button, tap Touch ID & Passcode.
2.
Scroll to Allow Access When Locked.
3.
Turn off every feature you don't need on the Lock Screen.
Path from the official guide by Apple for iOS 26, as of 3 Oct 2026.