On Mac, there is a new Shortcuts section at the top of your library. You can drag just about anything there to add a shortcut.
On iOS, shortcuts are found on a new star tab that is on just about every screen besides editing a note. To create a note shortcut, tap the star at the bottom of a note. For tags, you have to first view the tag, then open the shortcuts tab to find a ‘create a shortcut for this tag’ option at the top. I can’t figure out how to create shortcuts for notebooks yet—anyone have an idea?