Styles are contained in documents.

They come from templates.


What is the relationship between a Microsoft Word document and its template?


You can copy styles from one template/document to another using the Organizer.


If this is one or two styles, I would recommend saving them as a QuickStyle Set that you would be able to attach to any document or template. To do this, in a document with your style, remove all other styles from the Quick Styles Gallery. Then save as a Quick Styles Set.


Use of the Organizer to import particular styles can also be done using macros and a global template as described here: A Global StyleSheet in Microsoft Word?