Environments

Each Sitefinity Cloud subscription (project) includes a Production environment and one or more non-Production environments. This enables content editors and developers to make changes that can be tested/previewed without affecting Production.
Each Sitefinity Cloud environment (including non-Production) for each customer project is isolated - it has separate application and database resources, as well as dedicated Azure resources. Each Sitefinity Cloud environment scales automatically to ensure optimal performance and high availability.

In the Production environment, content editors can author content in an efficient and secure fashion, utilizing the Sitefinity content editing capabilities and content approval workflow.
Website visitors can access the public content via the website's public URL.

Deploying new functionality / customizations to Production is done via preconfigured deployment pipelines available in the Sitefinity Cloud Management Portal.

Depending on the use case, non-Production environments can be used by a variety of different users like website stakeholders and partner teams, including business users, content editors and technical team members (such as developers and QA specialists). A non-Production environment is completely separated from Production and can be used for developing new features, user acceptance testing (UAT), content authoring, as needed.

In a default setup, Sitefinity Cloud includes a non-Production environment called Staging, which is used for the development and testing of new functionality. You can purchase additional non-Production environments according to your needs.
Deploying new functionality to non-Production environments is done via preconfigured deployment pipelines available in the Sitefinity Cloud Management Portal. 
Site Sync can be configured between the different environments in the setup according to specific requirements of the customer. For example, an additional non-Production environment can be configured as Content Authoring - for staging and publishing content, where content changes can be easily synced to Production.