Personally I find it hard to read text when the background is white and the text is black. I recently found Word had a dark mode integrated into the word document. I initially used a crack by changing the background to dark grey and back to white when I go to print the file. (Alt > G > PC > → > ↓ > ↓ > ↓ > ↓ > Enter)
I am using Microsoft Office Professional Plus 2016 for this tutorial.
First go to Options to enable dark mode. File > Options > General > Office Theme: Uncheck Disable dark Mode.
Now that the the Disable dark mode is turned off you now have a dark mode option in the View tab. You can click that to toggle Dark mode.