For Zotero to work you need to install the program and the browser connector.
3/21/22: Zotero has released an app for iOS, but so far the app does not import references correctly. The app does allow you to read and annotate PDFs that exist in your library.
Below is an example of the Zotero client. Notice that it is divided into three segments--one for collections (far left), one that lists items within a collection (middle), and one that presents an individual item's metadata (far right).