Netlify allows developers to create and access build environment variables in a secure, private location within their project's dashboard, providing a convenient way to manage and share configuration settings. These variables can be set using the Netlify configuration file (`netlify.toml`) or through site settings, allowing for flexibility in how they are deployed and accessed. Environment variables can also be injected into shell commands, such as build and ignore commands, and are accessible through serverless functions, snippet injection, app code, and other means. This feature enables developers to keep sensitive information secure while still making it easily accessible to team members, reducing the risk of exposure to hackers.