Add-ons and plugins are used by people to improve the look and the feel of their programs. Different software makers need to be familiar with these so that you will know which ones they will use. The plugin will make it possible for a certain feature to become present in a current program.
Different programs support plugins. If this is the case, this means that customization is possible, and further changes can be made to enhance the program even more. The main difference between the add-on and the plugin is the programs that they are used for. Add-on is normally used for Firefox while Plugin is used for Chrome.