After understanding the difference between nodes and content types, let’s learn a new concept. Fields are Drupal's atomic data storage mechanism. They allow you to save discrete pieces of information which can be used for displaying, filtering, and sorting purposes.. Fields can be attached to nodes, users, taxonomy terms, blocks, and other Drupal entities. It is possible to share a field among bundles of the same entity. For example, you can share an image field among different content types (bundles) of the content (node) entity.