Xournal++ Mobile allows you to share Xournal++ notebooks across all your devices.
Simply take notes, sketch on images, edit PDFs or continue your existing notebooks on your Android device.
Xournal++ and Xournal++ Mobile are open source projects to provide an easy to use solution for students, scientists and creatives for sketching up anything you want.

* Use pressure-sensitive stylus for realistic painting and handwriting
* Sketch around and highlight in scanned images or photographs
* Display LaTeX formulas
* Intuitive UI
* Quickly access recent documents
* Share any .xopp file to Xournal++ Mobile
* Perfectly integrates with Nextcloud
* Native dark mode

Check out https://gitlab.com/TheOneWithTheBraid/xournalpp_mobile for more details on open source.