You would like to receive invoices in a PDF file format.
Heroku invoices are displayed in your Dashboard as HTML pages due to the need for displaying your usage, application, and add-on details. Invoices and application-based usage data can be expanded & collapsed on an as-needed basis to understand what contributes to your spending.
Conversion to PDF
You can convert Heroku invoices to PDF automatically from within the Dashboard. Print the invoice by selecting "Save to PDF" in the print dialogue option in your browser.