A torrent file is a small file that contains metadata about files and folders to be shared over the BitTorrent protocol. Instead of downloading a file from a single source, users can download pieces of the file from multiple sources simultaneously, which can speed up the download process. When a user opens a torrent file with a BitTorrent client, the client connects to other users (peers) who have the same file. This decentralized method of file sharing allows for efficient distribution of large files, such as movies, software, or games, while reducing the load on any single server.