When you need to let users select files—such as images, documents, or videos—directly from their device, the file input element is your essential tool. HTML provides the input type="file" element, which opens a file picker dialog for users. However, to actually work with the selected files in your application, you must use the File API in JavaScript. The File API gives you programmatic access to the files chosen by the user, allowing you to read their properties, preview content, or process the files before uploading them to a server.