Evernote is a note-taking and organizing app that allows users to save notes, web pages, photos, videos and other files across all their devices for easy access anywhere. It provides various features like notebooks to organize content by topic, tagging for easy searching, and sharing capabilities. The document outlines how to set up an Evernote account, create and organize notebooks, add different file types and annotations, and use it to create student learning portfolios and eBooks.