Step on how to change windows default app to dark mode on windows 10, after change all those default app background will become dark mode including your file explorer.
Table of - Content
1 - Go to Windows Settings.
First go to your Windows Settings by pressing Win + i key, after open locate to Personalization option from the grid view.
2 - Go to Colors Option.
After you have chooses Personalization, from the list of option at the left go to Colors option, scroll down until you see Choose your default app mode just change it from Light to Dark.