You can add Style Templates to the Template Organizer for re-use on other maps. You can add:
A "blank" style that uses the system defaults and contains no additional formatting. This is a good way to start from scratch to create a new style. You can go on to modify this style and save it for re-use.
A new style that uses the automatic style settings of the current map. Use this option if you modified the current map style and want to save it as a separate style template for re-use on other maps.
A style from a style file. This may be a file that you have received from a colleague, or a standard style that's been designed for use on all corporate maps or just for a particular project. Adding it to the organizer makes it easier to locate and use.
On the Tools tab, in the Templates group, click Map Styles.
Select a folder where you want to add the new style. (You can always drag it to a different folder later.)
Click Add New Style Template.
Then click on:
New Blank Style to add a style that uses the system defaults for all formatting.
From Style of Current Map to save the style settings from the current map as a discreet style and add it to the organizer list.
From Existing Style to add a style from a file to the organizer. Choose the style file from the dialog that appears.
Once the style is added to the list, you can rename it by clicking Rename under Template commands.