FTP is a method for transferring data to/from web servers via a different method than the standard http (Hyper Text Transfer Protocol) used to display web pages.
FTP software is designed specifically for file transfer and is written to more efficiently and safely download files free of errors. It is also used to upload files to your virtual, shared, or dedicated web server site.
FTP can also be used for direct downloads of files and images from a web server without being served from the public html directory via a means called anonymous FTP, or via a secure login. FTP access to a web server requires a password and username in order to gain access to the file and folder directories of a virtual domain, unless the server is set up to allow anonymous FTP - a useful protocol when allowing the public to freely download files or distributed software.