1 - Create a resource group, and then deploy a web app to the resource group.
2 - From the Automation script blade of the resource group , click Add to Library.
3 - From the Templates service, select the template, and then share the template to the web administrators .
Reference:
https://docs.microsoft.com/en-us/azure/azure-resource-manager/templates/quickstart-create-templates-use-the-portal