Zotero can be used on several different mobile browsers using a "bookmarklet." The "bookmarklet" is a link that saves items directly to the Zotero library from the web.
Instruction for setting up a Zotero bookmarklet are available on Zotero's Download Bookmarklet page.
The set up process will vary slightly depending on which mobile browser is being used. There is also a desktop version of bookmarklet available.
In Zotero, there will be a green arrow on the right side of the application. If clicked, it will spin to indicate that it is uploading your citations. Syncing your Zotero library can be useful if you use Zotero on multiple devices. Changes to the library on one device will be reflect on all other devices.
Follow the instructions below to sync the Zotero library.