All members of the Adobe Acrobat suite are proprietary software. These products are also not available on any Linux system.
Xournal++
Xournal++ (/ˌzɚnl̟ˌplʌsˈplʌs/) is a FLOSS note-taking software for PDF documents. It is a modern rewrite of Xournal which is extremely featureful.
- Website:
Okular
Okular is a FLOSS PDF reader by the KDE global community. KDE’s financial and legal matters are managed by a German non-profit with no direct influence on software development. Some of the formats Okular supports are “PDF, EPub, DjVU and MD for documents; JPEG, PNG, GIF, Tiff, WebP for images; CBR and CBZ for comics”. It also lets you annotate and sign documents, as well as view their table of contents.
- Website: