The default background color of Microsoft Word documents is white. You can change the background to a different color, gradient, texture or pattern. This presents you with an option of making your documents more presentable, colorful and easily readable for users.
The steps detailed below apply to Microsoft Word versions 2007 and 2010
Change Background Color (word 2010 and 2007)
Step 1- Go to Page Layout Tab(4th from left in the ribbon). In the Page Background options group, click ‘Page Color’.
Step 2- Click the color you wish to apply and it will be applied to all the pages in the document.
If you wish to see more colors, Click the More Colors option. That will bring up a palette and you have option to choose from thousands of colors and their variations.
Use Gradient as Background
Instead of applying a single color to the background, you can also apply a Gradient. Gradient is a combination of colors gently mixing into each other.
STEP 1- In the ‘Page Color’ click the bottom option ‘Fill effects’. A menu will appear. You can do the following in that menu

Use a single color in combination with white

Use two colors of your choice.

Use a pre-defined set of color combinations under ‘Preset’

You can also alter the transparency options.

Shading styles can also be changed. whether the two colors appear left and right of each other, top and bottom etc. In the example below, we have set the colors to appear diagonally.

Apply Texture to Background
Textures are colorful images or backgrounds that give an artistic touch to Word documents.
Instead of applying a single color to the background, you can also apply a texture. Sample textures are given in Microsoft Word 2010 and Word 2007.
Step 1- In the ‘Page Color’ click the bottom option ‘Fill effects’. From the menu that appears, click the Texture tab.
Step 2- You will be presented with a variety of built in textures, left click to select one and Click Ok.
Apply Patterns to Background
MS Word also lets you to apply patterns to document backgrounds. Patterns consists of small shapes or as the name suggests patterns of lines and curves. usually they are in black and white.
Step 1- In the ‘Page Color’ click the bottom option ‘Fill effects’. From the menu that appears, click the Patterns tab.
Step 2- You will be presented with a thumbnail gallery of patterns available in Microsoft Word, left click to select one and Click Ok.
NOTE: You can also choose a foreground and background color for Texture. Foreground color will be the color of lines or dots in the texture.
TIP: Make sure that the background applied should not make reading the text difficult.