How do I import bibliographies from my pre-Zotero papers written in Microsoft Word or other word processors?

You cannot directly copy-and-paste existing bibliographies into Zotero. You have several options for getting items from your pre-Zotero bibliographies into your Zotero for future use:

1. For very short bibliographies, search for each of the items in a large database that is compatible with Zotero, such as Worldcat.org, Google Scholar/Books. Import the bibliographic data for each item into your Zotero.
2. Zotero itself has resources for importing existing bibliographies: https://www.zotero.org/support/kb/importing_formatted_bibliographies