I am showing this for the PHP language. In Notepad++ Click on Settings -> Preferences Click on the New Document tab Change the Default Language to PHP See below inage To add an extension to load PHP editor for different extensions. Click on Settings -> Style Configurator In Language scroll down to PHP and click it. In below it will show default ext. Add your extensions at user exit. (Don't need '.'). eg: inc install module Click on Save & Close See below image for reference.