If you're just starting to learn then it probably doesn't matter too much. ASP.NET MVC and ASP.NET Core are very similar. WebForms (if that is what you mean by

If you're just starting to learn then it probably doesn't matter too much. ASP.NET MVC and ASP.NET Core are very similar. WebForms (if that is what you mean by Classic - not pre .NET JScript/VBScript) is different, and horrible. The MVC pattern is the same and you will be learning C# and Razor for both. The differences are in the details but many of the skills will be transferable. For example, the way bundling and minification are done is now different (built-in before and now JavaScript runners like gulp). Shameless plug; I cover these difference in my book "ASP.NET Core 1.0 High Performance": https://unop.uk/book https://unop.uk/book