The custom document task generates a billing document based on the HTML template that you provide in the task. This task is similar to the Custom Billing Document task. The only difference is that the custom document task does not attach the generated billing document to an object record.
To learn about task settings, template design, and data manipulation techniques, as well as how to view the output, see Custom Billing Document.
If you need to use custom fonts in your template, ensure to use font binary in the template instead of loading fonts from a website to avoid performance issues.