The `terraform` block allows you to configure Terraform behavior, including the Terraform version, backend, integration with HCP Terraform, and required providers.| Terraform block configuration reference | Terraform | HashiCorp Developer
Use the `backend` block to control where Terraform stores state. Learn about the available state backends, the backend block, initializing backends, partial backend configuration, changing backend configuration, and unconfiguring a backend.| Backend block configuration overview | Terraform | HashiCorp Developer
Version constraint strings specify a range of acceptable versions for modules, providers, and Terraform itself. Learn version constraint syntax and behavior.| Version Constraints - Configuration Language | Terraform | HashiCorp Developer