If you use the Zotero word processor plugin to add citations to your document and then open the document in another word processor, the Zotero citation links will be lost. To retain active Zotero citations when moving between programs, you can use the plugin to convert the document to a temporary format that can be safely transferred and then restore it in another supported word processor.
You can store the citations in your document in a way that is compatible with both Word and LibreOffice by selecting “Bookmarks” in the plugin's Document Preferences. This allows you to work on the same document with both Word and LibreOffice without going through the conversion procedure. However, storing citations as bookmarks does not work with footnote styles and may occasionally lead to citation corruption.
If you don't intend to use both Word and LibreOffice to edit the document, you should use the conversion procedure below.