Utilize to interact with Terraform Enterprise environments to build out your workspace.
This will consume the variables.tf file to auto populate the variables you have defined, and will even populate the default values.
The envVars.json file is there to setup API keys, and other keys that are typically utilized in your workspaces. It is setup to create not only environment variables, but also regular terraform variables that may be utilized by a provider, or need to be set everytime the environment is deployed.