You can define default attributes for text and objects.
For example, you can set up Keynote so that every time you click Table in the toolbar, the default table is added, formatted with the number of rows and columns, header and body text font, and border colors you’ve predefined.
To change an element’s default attributes, you create the element with the desired attributes, and then define the element for a specific master or for all masters in the theme. If you define the element for one master, the defaults apply to new elements on slides based on that master. If you define the element for all masters, every new element in the document uses the defaults.
For detailed instructions, see the following topics: