Next, you’ll see a Finder window filled with files that represent the various preference panes. These are the System Preferenes that come with macOS by default. (If you are looking for a third-party preference pane file, visit /Library/PreferencePanes
instead.) Each one has a “.prefPane” extension.
Scroll through the window until you locate the file representing the preference pane that you’d like to add to your Dock. For example, “DateAndTime.prefPane” is the file for “Date & Time” preference pane. Click and drag the preference pane file onto the file and folder shortcut area of your Dock, which is located near the Trash can.