Visual Studio Extensions are add-ons that enhance the functionality of the Visual Studio integrated development environment (IDE). They allow developers to customize their coding experience by adding new features, tools, and workflows. Extensions can improve productivity, streamline processes, and support various programming languages. These extensions can be easily installed from the Visual Studio Marketplace, where users can find a wide range of options, from code analyzers to user interface themes. Developers can also create their own extensions to meet specific needs, making Visual Studio a flexible and powerful tool for software development.