Okular

Okular is a Linux document viewer from KDE for reading files and adding annotations. It is intended for work with documents rather than general image editing or word processing. Users can open a document, navigate through its pages, and mark up content with notes or other annotation tools when review or study requires visible comments.

The application fits common reading tasks such as checking reports, lecture material, manuals, and forms on a desktop system. Its role is to display documents and support markup within that viewing workflow. Okular is distributed under GPL-2.0+ and GFDL-1.3 licensing, with the platform information here limited to Linux.