The following video shows how to add in-text citations and a bibliography into a Word document from your Zotero library
Google Docs includes Zotero (Z icon) in its toolbar. The following video shows how to add in-text citations and a bibliography into a Google Doc from your Zotero library. NOTES...
The presenter of the above video uses the Classic view when making a selection to cite a reference. "Classic View" is not the default option when you download Zotero, but it is a useful option to set up as your preferences:
The follow video shows how to change the existing referencey style of your document to another: