Browser extensions are small software programs that add specific features or functionalities to web browsers like Google Chrome, Mozilla Firefox, or Microsoft Edge. They enhance the browsing experience by allowing users to customize their browser, improve productivity, or access additional tools directly from the browser interface. These extensions can perform a variety of tasks, such as blocking ads, managing passwords, or providing quick access to social media. Users can easily install and manage these extensions from their browser's official store, making it simple to tailor their online experience to better suit their needs.