What does "Terraform apply" command do?

The "Terraform apply" command is fundamental in the Terraform workflow, as it is responsible for applying the changes that have been planned for your infrastructure. When you run this command, Terraform takes the desired state of the infrastructure—defined in your configuration files—and makes the necessary updates to reach that state in your actual cloud environment.

Before executing the changes, Terraform typically provides a summary of what will occur and prompts for confirmation. This ensures that the user has the opportunity to review and approve the proposed modifications before they are implemented. Thus, the command modifies the existing infrastructure, creates new resources if required, or destroys resources that no longer align with the declared configuration, making it a crucial step in managing infrastructure as code.

The other choices do not accurately describe the primary function of "Terraform apply." While configuration files are indeed run, the command specifically executes proposed changes rather than running without modifications or only for compilation purposes. Additionally, plugin installation is generally a separate process handled by other Terraform commands.