I would presume visionOS would support (out of the box) something like the Files app in iOS, which let's you open and read PDFs, as well as markup them.
Maybe someone who has tried visionOS beta can give a definitive answer here?
Can you read and markup PDF in visionOS?
Friendly bump here. Does visionOS support reading and annotating (markup) PDFs?
Since Apple Notes is supported in visionOS and Apple Notes now lets you view PDF inline, I'd suppose the answer is yes. But some confirmation would be nice.