The functionality of bibliographic management systems for mobile devices is often highly limited. But there are some solutions (both iOS and Android) available for Zotero (while there are no official Zotero apps for mobile devices). So you may access and edit your Zotero library on your mobile phone or tablet.

Zotero for mobile:
https://www.zotero.org/support/mobile

Zotero Reader web app tour:
http://www.youtube.com/watch?v=pAxEl4MAyeQ