Zotero is a reference management software that enables you to do all of the following:
Zotero has these useful features:
Download the software from the website
The software is compatible with Windows, MAC and Linux. Once you have download the software, download the Zotero Connector which sits in your browser. Then install Zotero Plug-in, which allows you to add citation and bibliographic references from Mendeley into your document
Refer to Zotero Documentation
You need both the Zotero Web and desktop to effectively use this software. The Web version allows you to access your 'Library' from multiple devices, import references, update your profile, etc. However, when you are working on your document, it works better with Zotero desktop.
While both referencing management software have Web and desktop versions and both assist you to manage your references, the following are some distinct features,
Click the blue tab 'Mendeley or Zotero' for detailed comparison
Social network comparison between Mendeley, Zotero, ResearchGate and Academia is also available here