Xournal++

Xournal++ is a free, open-source note-taking and PDF annotation application focused on handwriting, sketching, and markup. It supports stylus input, pressure sensitivity, layers, background images, and importing/exporting PDFs, making it well suited for annotating documents, taking lecture notes, and sketching diagrams.

Available for Linux, Windows, and macOS, Xournal++ is maintained by a community of contributors and offers features such as stroke smoothing, shape recognition, customizable too...