Install okular by entering the following commands in the terminal:
sudo apt update sudo apt install okular
Description:
universal document viewer
Okular is a universal document viewer with support for advanced document features, such as annotations, forms, and embedded files. . This package provides the document viewer application, plus plugins for a wide variety of document formats such as: * PostScript (PS) * Portable Document Format (PDF) * OpenDocument Text (ODT) * TeX Device independent file format (DVI) * XML Paper Specification (XPS) * G3 fax * various electronic book formats: ComicBook, FictionBook, and Plucker . This package is part of the KDE graphics module.
Homepage: http://www.kde.org/
Version: 4:17.12.3-0ubuntu1
Section: universe/graphics