Zotero offers word processing plugins for Word and OpenOffice.
Once installed, the plugin adds a Zotero toolbar to your word processor which allows you to add citations to your document while your write up your research.
To add a citation, click the first button ("Insert Citation") on the toolbar. Search for the reference you want to cite and press Enter. Zotero will add the citation at your cursor.
At the end of your paper, click the third button ("Insert Bibliography"). Your bibliography will appear, and new citations will be added automatically. Change bibliographic styles with the last button on the toolbar ("Set Doc Prefs").
Creating a bibliography using Zotero is very simple.
Highlight the references in your folder/file. Right click. Choose your reference style. The bibliography will open into a new window where you may edit, and/or copy the list.
Using Zotero to create in-text Citations and Bibliographies in Word documents
Zotero comes with the most common bibliographic styles, but you can add many more.
To install a style (Firefox):
The new style will appear in Zotero's style lists.