Cookie container means?

string outputXml = "";
            string url = "https://api.com/endpoint";
            string param = "?username=Jey&Password=Pass123";
            url = url + param;
            
            CookieContainer cookies = new CookieContainer();
            HttpWebRequest webRequest = WebRequest.Create(url) as HttpWebRequest;
            string contentType = "pplication/x-www-form-urlencoded";
            System.Net.ServicePointManager.Expect100Continue = false;
            webRequest.Method = "POST";
            webRequest.ContentType = contentType;
            //webRequest.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
            webRequest.CookieContainer = cookies;
            StreamReader responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream());
            string responseData = responseReader.ReadToEnd();
            responseReader.Close();
            webRequest.GetResponse().Close();

            var parsed = JObject.Parse(responseData);
            string token = parsed.SelectToken("access_token").ToString();

CookieContainer cookies = new CookieContainer();