It is possible to add custom styles to the ribbon in SharePoint 2013 (and SharePoint 2010 in that matter, the procedures are the same). This allows content editors to choose from your specific predefined styles easily to format their text.
Now how do we accomplish this adding our own styles to the Styles section in the ribbon? In this guidance I'll show you how to do it through SharePoint Designer. If you want to roll this out over multiple environments, i.e. in a development, test, acceptance, production (DTAP) street, it would be wise to add the CSS to a solution package and deploy it through a feature.
For a style in the Page Elements section, use the format: span.ms-rteElement-<yourowndefinedname>Note that instead of using span, you can also use H1, H2, H3, H4 which will then be wrapped around the text to which this Page Element style is being added
Within your class definition, add the following line which should be there for either of the two types of styles:-ms-name:"The name visual in the ribbon for your style";