How to change keyboard backlight color from blue to white in Dell G3 15 laptop

On the drivers page for your laptop, they list the "Alienware Command Center Application" under the "Application" category, the description says:

This package contains the Alienware Command Center application. The package includes Main Dashboard, Games Library, Game Profile Manager, AlienFX Lighting Manager (AlienFX compatible systems and peripherals only), Macro Manager (Supported peripherals and systems only). The Alienware Command Center (AWCC) is software that integrates applications in to a single interface that is designed to control features of your Alienware system.

Once you install this you should be able to adjust your lighting settings.