When you create a style, it becomes part of your style list. However, it will not show in the Style Gallery (Word 2007, 2010 and 2013) unless you specifically add it to the Style Gallery.
In order to see the styles, on the Home tab, in the Styles group click on the little arrow in the bottom right corner of the group.
This will open the Styles list, which you can then position and fix to the right-hand side of the Word window.
It is possible to choose what styles you want to be able to see when the list is open.
In order to do that, click on the Options button at the bottom of the list. This will open the following dialog box
Here you can select what styles will be visible in the list.
If you want a style to appear in the Style Gallery, find the style in the list and place your cursor on the line> When you do, a small down-pointing arrow will appear and if you right-click it, the following menu will appear:
The last option is Add to Style Gallery. Click that and the style, while still remaining in the style list, will also become a part of the Style Gallery. However, keep in mind that the Style Gallery is arranged alphabetically, so that the style could be invisible at first sight, and you may need to open up the Style Gallery to locate it.
Word 2003 does not have a Style Gallery, but it certainly has the Style List (it’s called Styles and Formatting).
To open the Styles and Formatting go to the Format menu and click on Styles and Formatting.