Variables are a critical component when building an application or managing Terraform configurations, providing modularity, reusability, and security. Managing variables can be a chore in complex code, but Terraform Cloud offers a robust system for variable management, including direct configuration management and UI-based access. Terraform Cloud workspaces provide isolation, allowing the definition of two types of variables: Terraform variables and environment variables, which set values that can be consumed by configurations during runs. The UI allows users to define and control variables, with sensitive labels indicating write-only values and HCL labels denoting code-interpolated variables. The UI also provides a description field for variable definitions, making it easier for teammates to understand workspace configurations. Additionally, the Terraform Enterprise Provider offers a simpler way to manage large quantities of variables programmatically or at once. Users can learn more about using variables in Terraform Cloud by signing up for a free account, visiting documentation, or exploring the HashiCorp Learn platform.