On the Home tab under styles check the more button to expand the style palette.
With Character styles, select text to apply styles
Themes comprise of a fixed colour palette and Fonts (Headings and Body text only). Once a theme (.thmx) is saved it can be across all Microsoft Word applications which is really useful when keeping continuity between documents.
If a colour palette is supplied the template provided will be supplied with this colour palette and Font styles as default.
These can be saved into your 'Themes' folder to be used in other Microsoft applications.