The protocol commonly used for transferring files over the internet is File Transfer Protocol (FTP). FTP allows users to upload and download files between a client and server across a network. It operates through a client-server model, where the client requests files from the server. FTP supports various commands for managing files, such as uploading, downloading, and deleting. Its simplicity and efficiency make it a widely used standard for file sharing, particularly in web development and hosting environments. Secured versions, like FTPS and SFTP, add encryption for safer file transfers.