$ sudo apt-get update
$ sudo apt-get install qpdfview-djvu-plugin 

qpdfview-djvu-plugin is installed in your system.

Make ensure the qpdfview-djvu-plugin package were installed using the commands given below,

$ sudo dpkg-query -l | grep qpdfview-djvu-plugin *

You will get with qpdfview-djvu-plugin package name, version, architecture and description in a table

qpdfview-djvu-plugin package basic information: