Notability is an app that allows you to take handwritten notes as if you were writing on a regular pad of paper. You can change ink color and the thickness of the line. You can also cut and paste different notes and move them around the page if you change where you think something should be. It is a basic app, that is easy for beginners to use, but still highly functional. You should use a stylus with this app. Although you can write with your finger, that is a lot harder to do clearly than you might imagine since you have been using a pen or pencil since you first learned how to write. If you click anywhere in this description you jump to the website for the app.