ASP.NET Core platform is a technology from Microsoft, designed for creating various kinds of web applications: from small web sites to large web portals and web services.
Introduction to ASP.NET Core

About creating web apps using ASP.NET
ASP.NET Core platform is a technology from Microsoft, designed for creating various kinds of web applications: from small web sites to large web portals and web services.
ASP.NET web forms are part of the ASP.NET web application infrastructure and are included with Visual Studio.