FTP, FTPS, SFTP and SCP are all protocols in which we communicate and transfer files between servers and computers. Here is a brief overview of what each one is.
FTP stand for file transfer protocol. FTP is a protocol most commonly used when uploading and downloading files from a servers. The least secure method of sending and receiving files since their is no encryption and your username and password are sent across the internet to the server in plain text.
Just think of FTPS as FTP over SSL. FTPS is just like FTP above, however its data gets encrypted over a SSL connection. It is a much more secure way of sending sensitive files.
Secure File Transfer Protocol should not be confused with the FTP or FTPS protocol. Basically this means you are using FTP over SSH. Although they server the same purpose in transferring files, SFTP is a lot more secure than FTP.
SCP or Secure Copy – is a method used to copy files from one SSH server to another. It is similar to the FTP protocol however you are executing a ssh copy from either a local server to a remote server or even from a remote server to a different remote server.