FileZilla is a powerful FTP-client. It has been designed for ease of use and with support for as many features as possible, while still being fast and reliable. The program offers support for firewalls and proxy connections as well as SSL and Kerberos GSS security.
Be aware that installing FileZilla on your computer might install some bundleware/malware on your machine. See this thread on the FileZilla forum: https://forum.filezilla-project.org/viewtopic.php?f=2&t=48441