Scratch Orgs: More Features and Supported Metadata Types

Designed to be ephemeral and easily recreated, scratch orgs are dedicated and configurable Salesforce environments that you can quickly spin up for many different purposes. They can be your own personal development environment, or you can create headless scratch orgs for automated tests. You can create scratch orgs if you turned on Dev Hub in your production org or have a trial Dev Hub org.

For more information, refer to the Salesforce DX Developer Guide.