App Services in Azure is part of Azure's PaaS and serverless solution, and you can use these services to host web apps, API apps, mobile apps, and logic apps. You can also host them inside App Service plans. Basically, this means that your apps are running on virtual machines that are hosted and maintained by Azure. 

Azure App Services offer the following capabilities:

• Multiple languages and frameworks: Azure App Services supports ASP.NET, ASP.NET Core, Java, Ruby, Node.js, PHP, and Python. You can also run PowerShell and other scripts, which can be executed in App Services as background services.
• DevOps optimization: You can set up continuous integration and continuous deployment (CI/CD) with Azure DevOps, GitHub, BitBucket, Docker Hub, and Azure Container Registry. You can use the test and staging environments to deploy your apps, and you can manage these apps using PowerShell or the CLI. 
• Global scale with high availability: You can scale up or out manually or automatically. This will be covered in the Scaling out and Scaling up sections later in this chapter.
• Security and compliance: App Services is ISO, SOC, and PCI compliant. You can authenticate users using Azure Active Directory or with social media logins, such as Google, Facebook, Twitter, and Microsoft accounts. You can also create IP address restrictions.
• Visual Studio integration: Visual Studio provides tools that can be used to create, deploy, and debug apps in App Services easily.
• API and mobile features: For RESTful API scenarios, Azure App Services provides turnkey cross-origin resource sharing (CORS) support. It also simplifies mobile app scenarios by enabling push notifications, offline data synchronization, authentication, and more.
• Serverless code: You can run scripts and code snippets on-demand without the need to provision or manage an infrastructure, and you only have to pay for the resources that you are using (see Chapter 9, Configuring Serverless Computing, for more information).