How to send a document to be printed from an API to iOS and Android?

I need to generate a document that will be printed in several platforms - iOS (Airprint), Android, and through a web browser. All of these platforms will be calling an API written in VB.NET which sends data back in an XML format. I would like to centralize the logic for generating the document to be printed so that it is done by the API for all platforms.

How would you recommend sending a document to be printed to these platforms? I was considering generating a PDF file on the .NET side and base64 encoding it. Then iOS/Android/Web would render the PDF and print it. Would you instead recommend generating an HTML file instead of a PDF? I'm mostly concerned with iOS and Android being able to render the document and print it.