You can add your own paragraph styles, rename existing styles, and delete styles you don’t want to keep. Any changes you make to styles affect the current document only, not all documents you create using Pages.
Note: You can’t add, rename, or delete a paragraph style in a document shared with others.
To add a new style, you first modify the text of a paragraph in your document to look the way you want, then create the new style based on that text.
In your document, click anywhere in the paragraph you want to base the new style on.
To see the Paragraph Styles pop-up menu, click the Text tab at the top of the Format 
sidebar, then click the paragraph style name near the top.
Click 
at the top of the Paragraph Styles pop-up menu.
A new style with a placeholder name appears in the pop-up menu.
Type a name for the new style, then click outside the menu to close it.
Click a paragraph that uses the style you want to rename.
In the Format sidebar, click the paragraph style name near the top, move the pointer over the style name you want to change, then click the arrow that appears.
If the text is in a text box, table, or shape, first click the Text tab at the top of the sidebar to see paragraph styles.
Choose Rename Style, then enter a new name.
You can delete a style from the paragraph styles list. You might want to do this to simplify the pop-up menu to include just the styles you use most.
Click anywhere in your document text.
In the Format sidebar, click the paragraph style name near the top.
If the text is in a text box, table, or shape, first click the Text tab at the top of the sidebar to see paragraph styles.
In the Paragraph Styles pop-up menu, move the pointer over the name of the style you want to delete, then click the arrow that appears and choose Delete Style.
If you try to delete a style that’s being used in the document, you’re asked to choose a style to replace the one you’re deleting.
Tip: You can drag styles in the Paragraph Styles pop-up menu to organize them.