FTP means File Transfer Protocol.
Used for transmitting files between client and server.
Using FTP a client can update, download, delete or rename the file from a server.

Active and passive mode:
In active mode the client starts connection.
Passive the server opens a port and listens and client connects to it.
Passive mode is secured.

Working with FTP:

Advantages:
Allows to transfer multiple files.
Resume option when connection is lost.
Ability to place queue to be upload or download.
Faster transfer than Https.

Disadvantages:
Username and passwords must be in clear text.
Inability to track what are the files have been uploaded.