In regular Terminal application in GUI you can use mouse to copy/paste via mouse wheel or sometimes even you can click depends on the application you run.
But in Linux console or simply in full text-mode by default mouse is not active and it has no use. If you want to active mouse in Linux text-mode you need to install gpm package which activates mouse in text-mode.
Here is the installation command of gpm in Ubuntu Linux.
$ sudo apt-get install gpm
Remember that after installation you need to reboot you computer/laptop to activate your mouse.
Enjoy having mouse in text-mode.