Add missing discovery endpoint info.

Author: JeethJJ

en/includes/guides/authentication/oidc/discover-oidc-configs.md

@@ -13,6 +13,112 @@ To get started, you need to have an application registered in {{ product_name }}
 
 ## Use the discovery endpoint
 
+### Discover the issuer
+
+OpenID Provider issuer discovery refers to the process of determining the location
+of the OpenID Provider. The following endpoint is responsible for revealing the OpenID Provider's
+issuer after validating the required parameters (Resource, Host and rel).
+
+```bash
+{{ product_url_format }}/.well-known/webfinger
+```
+
+Following information is required when making a request to discover the issuer's location.
+
+ <table>
+ <thead>
+ <tr class="header">
+ <th>Parameter</th>
+ <th>Description</th>
+ <th>Sample Value</th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr class="odd">
+ <td>Resource</td>
+ <td>Identifier for the target end user that is the subject of the discovery request.</td>
+ <td>acct:admin@localhost</td>
+ </tr>
+ <tr class="even">
+ <td>HostServer</td>
+ <td>Where the WebFinger service is hosted.</td>
+ <td>localhost</td>
+ </tr>
+ <tr class="odd">
+ <td>rel</td>
+ <td>URI identifying the type of service whose location is being requested.</td>
+ <td>http://openid.net/specs/connect/1.0/issuer</td>
+ </tr>
+ </tbody>
+ </table>
+
+**Sample request**
+
+=== "cURL"
+
+    ```bash  
+    curl --location 'https://localhost:9443/.well-known/webfinger/openid-configuration?resource=acct:admin@localhost&rel=http://openid.net/specs/connect/1.0/issuer'
+    ```
+
+=== "JavaScript - jQuery"
+
+    ```js 
+    var settings = {
+         "url": "{{ product_url_sample }}/.well-known/webfinger/openid-configuration",
+         "method": "GET",
+         "timeout": 0,
+         "headers": { "Accept": "application/json" },
+         "data": {
+            "resource": "acct:admin@localhost",
+            "rel": "http://openid.net/specs/connect/1.0/issuer"
+         }
+    };
+      
+    $.ajax(settings).done(function (response) {
+      console.log(response);
+    });
+    ```
+
+=== "Nodejs - Axios"
+
+    ```js 
+    var axios = require('axios');
+
+    var config = {
+         method: 'get',
+         url: '{{ product_url_sample }}/.well-known/webfinger/openid-configuration',
+         params: {
+            resource: 'acct:admin@localhost',
+            rel: 'http://openid.net/specs/connect/1.0/issuer'
+         },
+         headers: { 'Accept': 'application/json' }
+    };
+
+    axios(config)
+        .then(function (response) {
+            console.log(JSON.stringify(response.data));
+        })
+        .catch(function (error) {
+            console.log(error);
+        });
+    ```
+
+
+**Sample response**
+```json
+{
+   "subject": "acct:admin@localhost",
+   "links": [
+      {
+         "rel": "http://openid.net/specs/connect/1.0/issuer",
+         "href": "{{ product_url_sample }}/oauth2/token"
+      }
+   ]
+}
+```
+
+### Discover the issuer metadata
+
 OpenID Connect Discovery <!-- [OpenID Connect Discovery](https://openid.net/specs/openid-connect-discovery-1_0.html)--> allows you to discover the metadata such as endpoints, scopes, response types, claims, and supported client authentication methods of identity providers such as {{ product_name }}.
 
 Applications can dynamically discover the OpenID Connect identity provider metadata by calling the OpenID Connect discovery <!-- [OpenID Connect discovery](https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfigurationRequest)--> endpoint. The structure of the request URL is as follows: `<issuer>/.well-known/openid-configuration`.  
@@ -83,7 +189,7 @@ Applications can dynamically discover the OpenID Connect identity provider metad
 }
 ```
 
-## Get endpoints from the console
+## Use the console
 
 Some applications and SDKs are not capable of dynamically resolving endpoints from OpenID Connect discovery. For such applications, you need to configure endpoints manually.