When To Choose .NET Core And .NET Framework

This article clearly explains to the programmers when to choose the .NET core framework and the regular .NET Framework in simple terms.

There are two supported implementations for building server-side applications with .NET: .NET Framework and .NET Core. Both share many of the same components and you can share code across the two. However, there are fundamental differences between the two and your choice depends on what you want to accomplish. This article provides guidance on when to use each. 

It's worth reading this article to learn about the fundamental differences between these two frameworks.