I have updated the heading. But I believe key name we can give anything. That should not be an issue.
Yes, my API key is placed in the env variable only.
Postman uses API keys for authentication. The API key tells the API server that the request came from you. Everything that you have access to in Postman is accessible with your API key. You can generate a Postman API key in the API keys section of your Postman account settings.
You must include an API key in each request to the Postman API with the X-Api-Key request header. In Postman, you can store your API key as an environment variable. The Postman API collection will use it to make API calls.
However, the following is also relevant.
Using the API key as a query parameter
Requests that accept the X-Api-Key request header also accept the API key when you send it as the apikey query parameter. An API key sent as part of the header has a higher priority when you send the key as both a request header and a query parameter.