A single Pantheon site dashboard provides DEV, TEST, and LIVE environments by default. Additional "multidev" environments can be created on-demand.

Please refer to the following Pantheon documentation for detailed information on developing on Pantheon and managing your site dashboard's environments:

• Using the Pantheon Workflow - Understand the Pantheon WebOps workflow, and how to use separate Dev, Test, and Live environments for your Drupal or WordPress sites.
• Multidev - "Detailed information on using Pantheon's Multidev environment for your Drupal or WordPress site"
• Database Workflow - "Learn about the database that runs in your Pantheon site."
• Pantheon Filesystem - "Learn more about Pantheon's Filesystem"