How to pass the header, body data while using postmethod api

Question

i have two methods in webapi .one method is used for passing the data through the body at the time i can possible to pass through body in json format and also another method for passing the data through header in json format but i need to combine both json response to single jsonobject format how can do this.many of examples i seen it's not worked for me.please help me.

Body data code:

[Httppost]
[Route("api/Account/Login")]
public async task Login([From body]LoginRequest request)
{
 return response;
}

Header data code:

private HttpWebRequest CreateRequestObject(string ServiceURL)
{
   HttpWebRequest request=null;
   try
   {
      var _authkey=configurationManger.APPSetting["userkey"];
      request=(HttpWebRequest)WebRequest.Create(ServiceURL)
      request.Method="Post";
      request.ContentType="Application/Json";
      request.Headers.Add("AuthKey",_authkey);
   }
   catch(Exception ex)
  {
  }
 return request

}

please help me,
Thank u.