With Remastersys, we can backup entire Ubuntu file system which has been installed or added in file system.Also we can use the result of .ISO file to boot in friends computer/laptop with our additional program/software.
I say thanks to Ivan Kristianto,for this usefull tips. To install Remastersys,just open Appplication-Ubuntu Software Centre and search software named "Remastersys".
Then just run Remastersys to backup file system be an .ISO file then make it bootable with live cd or USB.