How to manage different configurations for different environments

I am working on a full stack app with a react frontend and a Django backend. But irrespective of the tech stack, what is the industry practice for having different configs for dev, prod, stage? Do I just store all of them in a single .env file? Is there a better way to do this?

For example, certain things are different in local development vs prod. The API url, other configurations, etc. How is this handled in the industry?