Merge pull request #189863 from GennadNY/gennadyk986

Gennadyk986

Author: tamarakhader

articles/postgresql/flexible-server/concepts-extensions.md

@@ -14,8 +14,20 @@ ms.date: 11/30/2021
 
 PostgreSQL provides the ability to extend the functionality of your database using extensions. Extensions bundle multiple related SQL objects together in a single package that can be loaded or removed from your database with a command. After being loaded in the database, extensions function like built-in features.
 
+
 ## How to use PostgreSQL extensions
-PostgreSQL extensions must be installed in your database before you can use them. To install a particular extension, run the [CREATE EXTENSION](https://www.postgresql.org/docs/current/sql-createextension.html) command. This command loads the packaged objects into your database.
+Before you can install extensions in Azure Database for PostgreSQL - Flexible Server, you will need to allow-list these extensions for use. 
+
+Using the [Azure portal](https://portal.azure.com):
+
+   1. Select your Azure Database for PostgreSQL - Flexible Server.
+   2. On the sidebar, select **Server Parameters**.
+   3. Search for the `azure.extensions` parameter.
+   4. Select extensions you wish to allow-list.
+     :::image type="content" source="./media/concepts-extensions/allow-list.png" alt-text=" Screenshot showing Azure Database for PostgreSQL - allow-listing extensions for installation ":::
+  
+After extensions are allow-listed, these must be installed in your database before you can use them. To install a particular extension, you should run the [CREATE EXTENSION](https://www.postgresql.org/docs/current/sql-createextension.html) command. This command loads the packaged objects into your database.
+
 
 Azure Database for PostgreSQL supports a subset of key extensions as listed below. This information is also available by running `SHOW azure.extensions;`. Extensions not listed in this document are not supported on Azure Database for PostgreSQL - Flexible Server. You cannot create or load your own extension in Azure Database for PostgreSQL.