If the Zotero Connector extension is connected to your internet browser, you will be able to automatically save citations from the browser to Zotero.
Zotero doesn't always recognize the type of resource in the web browser. If Zotero can't automatically collect citation information from a website, the website can still be saved to the library.
If citation do not show up on Zotero, syncing to the Zotero may be required.
For information on saving PDFs and attachments, see the "Organizing Your Library" tab.