Change the zoom/view percentage?

[gisrob]

The appearance of my notebook all of a sudden changed to be quite small and
difficult to read. It looks like it zoomed way out to some small percentage.
The font hasn't changed, neither has the page setup. Any suggestions on how
to recover the original default view?

 

[Erik Sojka (MVP)]

I'm not sure why the zoom level changed on you but there is a zoom button
on the Standard toolbar. You can also use Ctrl-Scroll on your mouse to
change the zoom level.

After recovering to the zoom level you want, OneNote should retain it
between sessions.