Labels are important tools that are used to sort and order your procedures. They can be edited at any time, but they are always a visible part of the procedure they are attached to. Everyone who is able to view the procedure will also be able to view the labels attached.
Though it is not possible to make labels private, it is possible to restrict a procedure so that only certain people will see it.
For more information on restricting a procedure, read: How to Restrict a Procedure and Keep it Private.