Zotero for iOS, currently in beta, is the best way to work with your Zotero library on an iPad or iPhone.

Zotero for iOS lets you work with your Zotero data no matter where you are:

• Sync your personal and group libraries
• View and edit item details
• Organize items into collections
• Generate citations and bibliographies in any of 10,000+ citation styles (APA, Chicago, MLA, etc.)
• Take notes on your research
• Read PDFs and add highlight, note, image, and ink annotations
• Easily save items and PDFs from the web to Zotero via the Share button in Safari or other apps (other browsers, Twitter, etc.)
• Avoid straining your eyes with full Dark Mode support, including while reading PDFs

Back on your computer, you can add PDF annotations you've made on your iPad or iPhone to Zotero notes and insert those notes into your word processor document with active Zotero citations or export them to Markdown. To access these annotations on your computer, you'll need to be running Zotero 6.

Please post to the Zotero Forums with any bug reports or feature requests. Be sure to mention “iOS”, “iPad”, or “iPhone” in your thread title.