In order to print in .NET MAUI, you must use the native platform APIs. On Windows, this also includes manually preparing the print preview. This example shows you how to print a PDF file on Windows, iOS, MacCatalyst, and Android.
The code is in the Helpers folder, with each platform having its's own class file. Here's the result when starting a print on Windows.
This is very document specific, you will need to do different work for different document types as this demo project is simply a place for you to get started.