This is the method for sharing Terraform configurations that fulfills the following criteria:
Keeps the configurations confidential within your organization
Supports Terraform's semantic version constraints
Provides a browsable directory
The Terraform Cloud private registry is a feature of Terraform Cloud that allows you to host and manage your own modules within your organization, and use them in your Terraform configurations with versioning and access control.

This is the workflow for deploying new infrastructure with Terraform, as it will create a plan and apply it to the target environment. The other options are either incorrect or incomplete.

In Terraform Cloud, speculative plan runs are not automatically started when changes are merged or committed to the version control repository linked to a workspace. Instead, speculative plans are typically triggered as part of proposed changes in merge requests or pull requests to give an indication of what would happen if the changes were applied, without making any real changes to the infrastructure. Actual plan and apply operations in Terraform Cloud workspaces are usually triggered by specific events or configurations defined within the Terraform Cloud workspace settings.References= This behavior is part of how Terraform Cloud integrates with version control systems and is documented in Terraform Cloud's usage guidelines and best practices, especially in the context of VCS-driven workflows.

This command will initialize the new backend and prompt you to migrate the existing state file to the new location4. The other commands are not relevant for this task.

The terraform fmt command is used to format Terraform configuration files to a canonical format and style.
This ensures that all team members are using a consistent style, making the code easier to read and maintain.
It automatically applies Terraform's standard formatting conventions to your configuration files, helping maintain consistency across the team's codebase.
References:
Terraform documentation on terraform fmt: Terraform Fmt