There are several options for how you want to create citations in Zotero.
If you've added the Zotero App and the Zotero toolbar is not appearing in Word, do these two things:
1. Close all your Word documents, quit the program completely, and reopen it. It should appear after restarting.
If that doesn't work then close Word again, and type step 2:
2. Go into your Zotero App and open Preferences > Select Cite > Just below the toolbar there's an option for Styles or Word Processors - Select Word Processors > Select ReInstall Microsoft Word Add-in
And now you should have the Zotero toolbar. But here's more help if you need it.
Creating full bibliographic citations in the Zotero App which is outlined below.