While there are no official Zotero apps for mobile devices, there are a few third party solutions.
Read more about these solutions: https://www.zotero.org/support/mobile
If you are a student or employee at Copenhagen University you can benefit from using Browzine:
1. Find, browse, and read your favorite scholarly journals
2. Be alerted when new issues are published
3. Export your favorite articles to Zotero from your BrowZine Library
You can use Browzine at androids and IOS devices.
Sync your references and PDF files in Zotero with ZotPad.
ZotPad is a free app, which works with iPad and iPhone.