Pages

Set a default font in Pages on Mac
You can set a default font and font size for the templates in the Basic category. Each time you begin a new document using these templates, your preferred font and font size are used.
For other templates, you can set your own fonts for paragraph styles, then save the template as a custom template. The next time you start a new document, choose your custom template from the My Templates section of the template chooser and just start typing.
You can set Pages to automatically start new documents with any template you designate.