In WordPress, widgets and plugins are both tools that can be used to add functionality to a website, but they are used in different ways.
A widget is a small block of functionality that can be added to a sidebar or other widget-ready area of a WordPress theme. Examples of things that can be added as widgets include a search bar, a list of recent posts, or a calendar.
Plugins, on the other hand, are more powerful tools that can add a wide variety of functionality to a WordPress website. They can be used to add new features, modify existing features, or even change the way that WordPress works. Examples of things that can be accomplished with plugins include creating a contact form, adding an e-commerce system, or optimizing a website for search engines.
The key difference is that widgets are small, simple tools that can be used to add specific types of functionality to a sidebar or other widget-ready area of a theme, while plugins are more powerful tools that can be used to add a wide variety of functionality to a website, throughout the entire website.