Within the Notes App you can draw on and edit your notes by following these easy steps:
Click on the central round icon to draw and edit your notes. You can highlight or insert simple drawings interacting with the screen of your device.
Edit allows you to select text and change the thickness and colour of your strokes. In order to change the thickness, select the pen icon at the bottom of the screen (the first).
The second pen icon is the highlighter. You can change the color of your pen and highlighter with the options provided in the color palette. Select the pen or the highlighter, then change the color.