Software plugins are small programs that add specific features or functionalities to a larger software application. They allow users to customize and enhance their experience without altering the core software. For example, a web browser like Google Chrome can use plugins to block ads or manage passwords. Plugins are commonly used in various applications, including content management systems like WordPress and graphic design software like Adobe Photoshop. By installing plugins, users can easily extend the capabilities of their software, making it more versatile and tailored to their needs.