unlock a preference pane
To unlock a preference pane, click the lock at the bottom left, then do one of the following:
Enter an administrator name and password.
Place your finger lightly on Touch ID (if your Mac has Touch ID and it’s set up to unlock your Mac).
Double-click the side button on your Apple Watch (if your Mac supports unlocking your Mac with Apple Watch).
Note: For some preferences, you must enter an administrator name and password—you can’t use Touch ID or Apple Watch.