I just spent a frustrating day myself trying to use HTMLview to look at a PDF in a way which worked well across all screen sizes.
In the end, I asked whether the data was available in a different format. It was, and life became wonderful again.
If you have to use PDF, the HTMLview sample shows a simple way to display a PDF. It doesn’t sound like it does everything you need. For that, you’ll need a library which converts the PDF to HTML. PDF.js seems to be popular for this: