Visual Studio has many tools that enable developers to easily interact with Azure. These are tools like the Cloud Explorer for Visual Studio 2017, Visual Studio Server Explorer, the main Visual Studio login, and even being able to right-click in the Visual Studio Solution Explorer to deploy a web project to Azure.
One of the capabilities in the Web Apps Service is placing your Azure resources in a non-internet routable network that you can control access to. These networks can be connected to your on-premise networks using VPN technologies. For example, with VNET integration you can enable access from your web app to resources running on a virtual machine in your Azure virtual network.