Word 2013 Page Background Colour

At "Page Layout" tab find the "Page Color" drop down arrow and choose a color. Once page color is changed,  you will have to save to the normal template, "Normal.dotm."

The Normal template is most likely stored in the Template folder in Microsoft Word. Open the Normal template from the Template folder, then make the page color change and "Save." New Word documents should show the new page color.  

How about other existing documents?

In the past, in the pre-Windows 7 era, we can change it in the theme and all documents, including excel etc, will have the same colour and even existing documents. Why can't we have that feature back?

As stated by TomGove, other color can be easier to the eyes.

How about other existing documents?

In the past, in the pre-Windows 7 era, we can change it in the theme and all documents, including excel etc, will have the same colour and even existing documents. Why can't we have that feature back?

As stated by TomGove, other color can be easier to the eyes.

As others have said, you can change the background color in the template you are using. It will then be used for all subsequent documents you create in Word.

On the other hand, if you mean that you want to change the color of the ribbon and the application background, then you will have to wait for Office 2016, which offers more possibilities in that respect.