Just put EditableSign.jar in the plugins folder.
You can Sneak + Right-click to edit the sign which is already placed! (only if you have "editablesign.edit" permission)
If WorldGuard option is turned on , you would need to set either USE = allow or INTERACT = allow (the latest WG 6.0 uses INTERACT flag).
This plugin also supports NoCheatPlus plugin. (tested against 3.12.0 - b793)
You can also edit Essentials' signs ([Sell], [Buy], [Disposal], etc.)
This plugin is based on libraryadict's previous work (SignMagic). He has been contacted and was ok about adding 1.8 support as well as WorldGuard support.
Permission Node:
Donation: It would be greatly appreciated for your donation to continue providing support for this plugin.