Google Drive has supported 3rd party apps for quite a while now and many of those apps are quite helpful to students. Beginning today Google Documents and Google Sheets now contain a new way for students to add even more functionality through 3rd party services. Add-ons for  Google Docs and Sheets allow any Google Drive user to add new functions to their documents and spreadsheets. To access Add-ons just open a new Google Document and open the new “Add-ons” drop-down menu to browse for add-ons.

Applications for Education
Some of the Add-ons for Docs and Sheets that jump out as being particularly useful to teachers and students are EasyBib for creating bibliographies, Kaizena shortcut for adding voice comments to Google Documents, and Table of Contents.