Response is a TIdHTTPResponse property used to specify the header values and optional content received in a message from the HTTP server. Response headers allow the server to pass additional information about the values returned for an HTTP Request. 

Response is used in the protected method that performs the HTTP transfer, or in Head when retrieving only the header values for the resource identified in URL. 

Response contains the raw data for headers received in the HTTP response, and also copies header values into propeties for the object instance. Response may also contain the raw data for Cookies maintained by CookieManager in the HTTP client. 

Response is used when capturing the headers, cookies, and contents for an HTTP response after a Request. 

Use Request to examine header values to be sent in a request to the HTTP server.

Request 

DoRequest 

TIdHTTPRequest 

TIdHTTPResponse