Xournal

Xournal also X Journal is a note-taking, sketching application on GNU/Linux. It is intended for working with stylus. But still I tried it using on my laptop using touchpad. Initially I found some problems simulating stylus using my touchpad but then I was trained to. Before sharing some features and hot to use it, i'll show some sample document which I used as an exercise while studying.

 

So, Xournal is a full-featured note-taking application. You have "Text Mode" for typing text, "Pen Mode" for writing using stylus or touchpad, "Ruler Mode" to draw lines( I did not use this mode while creating this document), "Highlighter" to highlight some piece of text. Also an "eraser" which you need a lot initially.
Also switching between these modes fairly simple and you can easily remember the shortcuts.

Xournal KeyBoard Shortcuts

Mode	KeyBoard Shortcut
Text Mode	Ctrl+Shift+T
Pen Mode	Ctrl+Shift+P
Ruler Mode	Ctrl+Shift+L
Eraser Mode	Ctrl+Shift+E
Highlight Mode	Ctrl+Shift+H

There are some more options which I haven't explored. You can export the file as a pdf file. There are various other options which you can play around with it.

Final Verdict: Xournal  is worth trying and you won't be disappointed.