How to get "Blender GNU GPL v2 license"?

I am changing some codes in the source file of the blender and I want to sell it to people through gumroad. Do i need gnu v2 license? If yes then how?

You can sell code modifications under the existing GPL v3 license. Add-on and theme developers already do this. Although if you compiled the code, you would have to provide the source files to anyone you give the compiled binaries to if they requested the source code.