A quick way to change an object’s appearance is to apply an object style to it. Every theme includes object styles—combinations of colors, borders, shadows, and other attributes—that match the theme.
If you customize the appearance of an object (text box, shape, table, or chart) and want to apply these same changes to other objects in your presentation, you can create a new object style. The new style is saved along with the object styles that come with the theme.
Select an object, then click a style at the top of the Style pane of the Format inspector.
Click the left or right arrows to see more styles.
Select the object with the changes you want to save as a new style.
In the Style pane of the Format inspector, navigate to the last pane of styles by clicking the triangle to the right of the styles.
Click 
to add your style.
The style appears last, but you can drag it to another location.
You can change the order of the styles in the Style pane.
Click and hold the style you want to move until a gray box appears around it then disappears.
Drag the style to a new location.
To move a style from the one pane to another, drag it over an arrow to open the other pane, then drag it to where you want it.
To delete a style, Control-click it, then choose Delete Style.
To quickly change the appearance of all objects that have the same style applied, redefine the style, then reapply it to all the objects.
Select one of the objects whose style you want to change, then modify its appearance so it looks the way you want.
Select the object you just modified (if you deselected it).
In the Style pane of the Format inspector, Control-click the style, then choose “Redefine Style from Selection.”
Click OK.
All objects that use the style are updated with the new style.