If you have additional information you'd like include on all of your billing documents, you can add a footer for statements, superbills, and invoices.
To add a footer:
- Go to My Account > Settings > Documents
- Enter the information you want to include in the Footer Information field next to the billing document type (Statements, Superbills, or Invoices)
- Click the Save button for each billing document type that you update
The footer will appear at the bottom of your billing document: 
Note: A footer that you save for any billing document type will be included in all of those billing documents moving forward, for every client. This is a practice-wide setting.