Hello @Renu Razora
For throughput widgets, you can navigate to the app service in the Azure Portal and click "Monitoring" on the Overview page you will see prepopulated graphs such as HTTP 5xx, Data In/Out, Requests and Response Time. You can click the pin button in the top right corner of the graph to add to any predefined or new Dashboard.
For more widget graphs, you can select "Metrics" from the left-hand menu select the metric dimensions you want to display, e.g., Connections, IO Read, IO Write, by an aggregation. You can then elect to save this graph as a widget to a dashboard by selecting the "Save to dashboard" option in the upper toolbar.
To learn more about monitoring an app service, please see Monitor App Service with Azure Monitor - Azure App Service | Microsoft Learn