im trying to make signs editable in my game so you can label stuff but im not sure how do to it
Assuming your sign is SurfaceGui dependent - you could use a ClickDetector to register mouse clicks and have a traditional ScreenGui containing a TextBox. Then, when FocusLost occurs on the TextBox - just update the SurfaceGui's label. This solution would probably aptly suite what you're looking for.
It is recommended that you provide some code which you have already tried to work on so that we can critique it rather than working from scratch!