Drupal, out of the box, already allows you to send emails. However, there are distinct advantages to using a service like Mailchimp to send emails and maintain your mailing lists.
In this tutorial, you’ll learn how to integrate Drupal and Mailchimp.
The Mailchimp module integrates Mailchimp and Drupal by allowing Drupal to connect via Mailchimp’s API. This module also comes with a few submodules. Each submodule provides additional functionality that leverages Mailchimp’s features.
Go to Source