We’re in the process of updating the documentation for Zotero 5.0. Some documentation may be outdated in the meantime. Thanks for your understanding.
How does the Import from Clipboard feature work?
Import from Clipboard allows you to import items from the raw code of any supported format (RIS, BibTeX, etc.). Many websites post the bibliographic data for items in their raw form. To add these items to your Zotero library, select and copy the code from the site, then import through the menu option in the Actions button of the Zotero toolbar, or by the keyboard shortcut (Cmd-Shift-V/Ctrl-Shift-V).