The three workflows for managing Terraform runs in HCP Terraform are UI/VCS, CLI, and API-driven. The UI/VCS workflow is the simplest and most push-button method, ideal for organizations seeking simple traceability and transparency, GitOps workflows, or easy setup of collaborative provisioning workflows. In contrast, the CLI-driven workflow offers more flexibility but requires a steeper learning curve, suitable for developers comfortable with Terraform's CLI tools and those who want to integrate it into existing CI/CD pipelines. The API-driven workflow is the most flexible but also has the highest learning curve, necessary for custom workflows integrated with specific toolchains or requiring granular controls for each step of the workflow. Each workflow has its unique setup, maintenance, and security considerations, making it essential to evaluate which one suits the organization's needs and skill levels.