How to Install SSH Server in Ubuntu Linux

SSH Server is a secured, encrypted way to make connections to remote hosts or servers. A SSH server accepts connections from SSH aware clients. Enabling public-key authentication. Transferring files and directories between computers over a secure connection. You can run shell and X based programs remotely using SSH.

Install SSH Server
$ sudo apt-get install openssh-client openssh-server

How to SSH into a remote Ubuntu machine with ip address 192.168.0.1
(Assuming that the remote Ubuntu machine has installed SSH Server service. or install $sudo apt-get install openssh-client)

$ ssh username@192.168.0.1 ( now it will display an authentication warning then press yes )

How to copy files/folders from a remote Ubuntu machine into a local machine (scp) 
(Remote Ubuntu machine IP address:192.168.0.1,Remote files/folders location: /home/username/remotefile.txt
Local machine save location: . (current directory)
$ scp -r username@192.168.0.1:/home/username/remotefile.txt

How to SSH into a remote Ubuntu machine from a Windows machine?

Download and run PuTTY

How to copy files/folders from/into a remote Ubuntu machine from a Windows machine

Download and install  WinSCP