Giving yourself space
If you have separate containers of information on your page and you are doing a lot of editing, then you may find you need to add space between the containers or take space away.
Insert Space works between containers, as well as objects that are not in containers, to fix any spacing problems. You can insert space vertically or horizontally. Although the feature is called Insert Space, you can also use it to reduce the space between containers.
Fun Fact
The OneNote team internally called this the Wiping tool for the longest time. It makes sense, as it started as a wiper to push everything down the page; but, at some point, the tool was modified to work either way – adding space or shrinking space. The wiper analogy just didn't work well anymore, but the OneNote team never really found a name that made sense – so it stuck with Insert Space, even if that's not all it can do.
Although you know how to move a container, sometimes...