In this article you’ll see how to install Okular in Ubuntu step by step. Okular is a universal document viewer based on KPDF for KDE 4, with support for advanced document features, such as annotations, forms, and embedded files. This means Okular works on multiple platforms, including but not limited to Linux, Windows, Mac OS X, *BSD, etc. It supports a multitude of formats. from PDF files to OpenDocument files. It’s not limited to solely reading files though, it can do way more.