You can now create custom tags to insert anywhere in your notebooks. For more information on custom tags and searching custom tags, read this blog – Custom tags available soon in OneNote
Also, tags in your notebook and pages now appear in your search results.
An error occurred while saving the commentColton Pepper commented
I'm afraid I don't see these new features and I even downloaded and installed the most recent update from Microsoft's site. The GUI does look different but I'm not seeing how to search for tags. Thinking that maybe it was a different tab in the Ribbon, I tried to customize the ribbon but it's grayed out. Not sure why but nothing I do allows me to customize the ribbon. Why have that as an option if you can't click it?
I verified that I am on the version specified in the announcement.