It is possible to modify Zotero by using plugins. Your Zotero-plugin for Word or Libre Office is one example. Have a look at and search for the page “Zotero plugins” at zotero.org to explore. Note! These plugins are created by other Zotero-users, hence not all plugins will be perfect. If in doubt, read a review of a plugin before you install, or uninstall if you notice any bugs.
In order to install a plugin, go to zotero.org > Plugins and search for the plugin you want. Click on the link; you will now be redirected to another website.
"Google Scholar Citations for Zotero" is a plugin that lets you see how many citations an item has in Google Scholar.
When you have installed the plugin, mark one or several items in your library, right click, and choose Update citations. Citations show up in the field Extra in the item metadata, under the variable "ZSCC".
Oftentimes, reference styles demands that the DOI for online articles be included in the reference list. However, DOI's may sometimes be missing or incorrect in Zotero. "Zotero DOI Manager" can be used in order to correct this.
When you have installed the plugin, mark one or several items in your library and right click. Under the option Manage DOIs you can know choose among following options:
DOI's show up in the Extra field in the item metadata, under the variable "DOI".