The FHFA Appreciation Report is a simple pre-made & pre-formatted option for staying in touch with customers. Because of this there aren't a lot of customizations available at this time. The only areas you can customize are the graph title and the footer information.

Customizing the Graph Title is covered in this Help Center article.

To change your footer information you'll set that up in Agent Branding. See this Help Center article to learn more about Agent Branding.