Depending on your settings Safari may not automatically open the file. Use Control+ Click and select "Download linked file to..." to save the file to your desktop or some other easy to remember location. Double click the file to open. Click "Open", then click "Install". The Safari capture icon will show up as a little box to the left of the address bar.
Zotero integrates with both Microsoft Word and LibreOffice.
The word processor plugins are bundled with Zotero and should be installed automatically for each supported word processor on your computer when you first start Zotero. In Microsoft Word, this adds a Zotero tab. In LibreOffice, this adds a Zotero toolbar.
You can reinstall the plugins later from the "Cite" → "Word Processor Plugins" pane of the Zotero preferences. If you're having trouble, see Manually Installing the Zotero Word Processor Plugin or Word Processor Plugin Troubleshooting.
If you previously installed the Firefox versions of the word processor plugins into Zotero 5.0 or Zotero Standalone 4.0, you should uninstall them from "Tools" → "Add-ons."
The official Zotero iPad and iPhone app is available on the App Store.
The mobile version of the Zotero web library also allows you to access and edit your Zotero library on your tablet or mobile phone.
You can also save items to your Zotero account using zotero.org/save.