A file is a named collection of information stored on a device or service. It might hold a photo, a document, or a song. Think of it as a labeled folder in a cabinet: the name helps you find the information again.
On a website, people may download a file to their device or upload one from their device. The file name and type can help show what it contains, such as a PDF document or a picture.
Before sharing a file, check that it is the intended version and does not contain information you want to keep private. Use a clear name so it is easier to recognize later.