Some FTP Servers allows anonymous login. Meaning is that, some FTP Servers allows users to login without authentication. Usually username "anonymous" is used to login for anonymous login to FTP Servers. Anonymous FTP is used to provide access to an FTP server, to download the files which are publicly available for download. For example; a product brochure.
Anonymous FTP Server accounts can be accessed by an internet browser by using the URL’s protocol part as ftp:// instead of http://, and then the IP address of the FTP server.
While configuring and allowing the anonymous login to an FTP server, main point to note is never allow access to the FTP root directory, which contains sensitive documents or files. Instead, create a root folder only for anonymous user access, which contains only publicly distributable files.
Please visit following link to learn how to add anonymous user account in FileZilla FTP Server.