Comprehensive and Detailed in-Depth Explanation:terraform initretrieves and caches providers and modules, butonly for explicitly declared modulesin the configuration.
* If a module isadded or updated, terraform init needs to be re-run to download the new version.
* Terraform does not automatically cache all remote modules unless they are explicitly referenced in the configuration.
Official Terraform Documentation Reference:terraform init - HashiCorp Documentation

This is what you must do to successfully retrieve this value from your networking module, as it will expose the attribute as an output value that can be referenced by other modules or resources. The error message indicates that the networking module does not have an output value named vnet_id, which causes the reference to fail.

The terraform refresh-only command is intended to detect state file drift. This command synchronizes the state file with the actual infrastructure, updating the state to reflect any changes that have occurred outside of Terraform.

This command will initialize the new backend and prompt you to migrate the existing state file to the new location3. The other commands are not relevant for this task.

The terraform import command is used to import existing infrastructure into Terraform's state. This allows Terraform to manage and destroy the imported infrastructure as part of the configuration. The terraform import command does not modify the configuration, so the imported resources must be manually added to the configuration after the import.
References = [Importing Infrastructure]