WordPress Plugins are small applications that extend the functionality of WordPress. They are literally plugged in to extend functionality or add new features to your WordPress websites.
WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. They make it easier for users to add features to their website without knowing a single line of code.
There are thousands of WordPress plugins available for free at the official WordPress plugin directory. In addition to free plugins, there are commercial ones available from third-party companies and developers.