In Microsoft OneNote, you can easily customize the color and thickness of your pen while handwriting or drawing notes.
Change the color of the selected pen
On the Draw tab, select the pen you want, and then tap the arrow next to the pen to change the color. If you want to switch color in mid-drawing, just tap another color at any time.
Sixteen solid colors are available on the menu, with more available when you tap More Ink Colors.
If you are an Office 365 subscriber, there are an additional eight effects available: Rainbow, Galaxy, Lava, Ocean, Rose Gold, Gold, Silver, and Bronze.
Change the thickness of the selected pen
On the Draw tab, select the pen you want, then tap the arrow next to the pen to change the thickness.
There are five pen thickness settings ranging from .25 mm to 3.5 mm. Select a thickness or use the plus or minus sign to make your pen thicker or thinner.
This feature is currently not available when using Microsoft OneNote on iPhone.