Okular is a document viewer gaining widespread support on Reddit, a popular community platform. The app developed by KDE, an international free and open-source software community, allows you to read files in various formats such as PDF, Tiff, DjVu, Comic Book, EPub, etc. It is the best free PDF reader for Linux, Windows, Mac OS X, and many other OS, which assists you in opening, annotating, and bookmarking PDF documents. Okular is highly praised by a number of Reddit and PDF users for its small size and free service.