Microsoft OneNote lets you easily switch between using the keyboard to type text and using a pen to handwrite or draw notes with the tap of a button.
Whenever you open or create a page in Microsoft OneNote, it starts out in text mode. To begin typing text, tap anywhere on the page, and then use the on-screen keyboard to type and format notes.
To switch to drawing mode at any time (for example, to draw a sketch in the middle of typed notes), tap the Draw tab, select the pen, color, and stroke thickness you want, and then move your finger or stylus over the page to draw or write.
To exit drawing mode and return to text entry, tap the Text Mode button on the Draw tab, and then tap anywhere on the page to display the on-screen keyboard again.
This feature is currently not available when using Microsoft OneNote on iPhone.