When a notebook section in OneNote Online already has a lot of pages in it and scrolling through them all takes too long, you can easily create as many additional sections as you need to better organize your notes.
At the bottom of the page list, click + Section.
In the Section Name dialog box, type a meaningful description for the new section, and then click OK.
You can organize sections by dragging their names up or down in the list.
Tip: If you accidentally create a section that you don’t need, right-click (PC) or Control-click (Mac) its name, and then click Delete.