Add-ons allow users to add or increase the functionality of an application, use themes to their liking and manage new content types.
Plugin add-ons are small programmes that extend the functions of the main plugin. For example, there are WordPress plugin add-ons that add specific functionality to the content management system, such as form creation, theme customisation, SEO optimisation, etc. Plugin add-ons differ from browser add-ons, which are programmes that extend the functions of the browser itself, such as translation, ad blocking, web page capture, etc.