Maven plugins are extensions to the core functionality of Maven. They provide additional capabilities for the build process, such as generating documentation, running tests, and packaging the project. Plugins are defined in the POM file and can be executed using the command line or through an IDE.

Maven plugins can be used to perform a wide range of tasks, including:

1. Compilation: Maven includes a Java compiler plugin that can compile source code, as well as other plugins that can compile other programming languages, such as Groovy or Scala.

2. Testing: Maven includes a test runner plugin that can run unit tests and generate reports on test coverage and results.

3. Packaging: Maven includes plugins that can package the compiled code into various formats, such as JAR, WAR, or EAR files.

4. Deployment: Maven includes plugins that can deploy the packaged code to remote servers or repositories, such as Apache Tomcat or Maven Central.

5. Documentation: Maven includes plugins that can generate project documentation, such as JavaDoc, as well as plugins that can generate project websites and reports.

Maven plugins can be used to customize the build process and automate repetitive tasks, making it easier to manage and maintain projects. They can be developed by anyone and published to a central repository, so they can be easily shared and used by other developers. Plugins can also be configured to execute automatically during the build process, allowing for consistent and reliable builds.