Modules offer additional or alternate features as image galleries, custom content types and content listings, WYSIWYG editors, private messaging, third-party integration tools, and more.
Some of the most commonly used contributed modules include:
Content Construction Kit (CCK): allows site administrators to dynamically create content types by extending the database schema. “Content type” describes the kind of information. Content types include, but are not limited to, events, invitations, reviews, articles, and products. The CCK Fields API is in Drupal core in Drupal 7.
Views: facilitates the retrieval and presentation, through a database abstraction system, of content to site visitors. Basic views functionality has been added to core in Drupal 8.
Panels: drag and drop layout manager that allows site administrators to visually design their site.
Rules: conditionally executed actions based on recurring events.
Features: enables the capture and management of features (entities, views, fields, configuration, etc.) into custom modules.
Context: allows definition of sections of site where Drupal features can be conditionally activated
Media: makes photo uploading and media management easier
Suppose, I would like to install ‘Administration menu’ module to increase default backend menu’s functionality so that I can easily access all admin panel’s functionality.






Now we have two menu Dashboard menu bar. One is default and another from new install module. So, i need to uninstall previous toolbar/dashboard menu.