Shifter is a full-service software-as-a-service hosting solution. While that sounds like a mouth-full, in short, it's a WordPress hosing solution.
Each time you start a site on Shifter that site is a new WordPress installation. From there you can modify or edit as you need or you can import an existing site following our Shifter Migration Guide.
On Shifter, WordPress runs in a secure container that can power on and off. While the container is running you can edit, update, and access your site.
After your done editing, you build a Static version of your WordPress site and deploy that. The complete Static version of your site is called an Artifact.
To update and change your Artifact, power on the WordPress container make your changes and build a new one.
Simple as that!