One of the Charms in Windows 8 promised to make it easy to share content between applications – rather than copying & pasting, maybe it would be better to allow the source application to provide some extra context to the destination app. When it works well, app-app sharing is really useful, but it maybe didn’t take off quite as much as expected.
The Sharing icon from Windows 8.x and early Windows 10 versions was the 3-blobs-in-a-circle which does looks a lot like the Ubuntu logo for some, and doesn’t necessarily convey the meaning of sharing to others. One of the tweaks in the Creators Update was not only a newly-designed icon, but a new Sharing UI that aims to simplify the process further.
If you are using a suitable Windows app (like Edge or Photos, for example), which touts the new sharing icon (the one with the arrow leaping out of the box), then when you choose the Share action, a UI will show up that lists all the apps that could be the target for Sharing, and a link to the Store to find more.
Sharing a page from Edge to OneNote, for example, will put a thumbnail image if available, a description of the page, and will let you add your own verbatim notes before saving the content as a new page in your notebook.
There are a few Clipboard apps which can be handy for sharing content so you can paste it into an old fashioned app that doesn’t support the Share method. Some “traditional” Windows apps – like the venerable Windows Explorer – are Share enabled, even though their icon may still be using the old design for now (and some Store apps have the same design lag – the Store App itself being one of them…)