Your first step to creating a PWA in Visual Studio 2019 (I used the Community Edition Preview) is to select the Blazor App template in the File | New Project dialog. After starting the Blazor App ...

That code can be written in higher-level languages -- like C/C++/Rust and more -- and targeted to WebAssembly code to run in the browser. For C# coders, Visual Studio IDE and VS Code would be natural ...