It's easy to create a bibliography from your Zotero library. Here are three methods.
Zotero offers word processing plugins for Word and OpenOffice. The plugin adds a Zotero toolbar to your word processor that allows you to add citations to your document while you write.
To add a citation:
At the end of your paper, place your cursor where you'd like your bibliography to appear and then 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.
You can drag and drop references from Zotero into your document! This works with any word processor including Google Docs. Change the default style under Preferences on the "gear" menu.
Select the references or collections you want to include. Hold the control key and click to select multiple items. Right-click one of the selected items and choose Create Bibliography. Choose the bibliographic style you want, and select the output format: Save as RTF or HTML, copy to clipboard or print. (The RTF file format is compatible with all word processors.)