Hey @Umesh 
Looking at the Coin API docs, you can send your API key using a custom header or a query parameter.
To pass your API key as a custom header, manually type X-CoinAPI-Key as your Header Key and enter your API key as your Header Value:
To pass your API key as a query parameter, add apikey as a URL Parameter followed by your API key:
Your final URL should look like this: https://rest.coinapi.io/v1/assests?apikey=YOUR_API_KEY
Let me know if that helps!