How can I generate downloadable PDF from the EPI? Which tool / functionalitiy is available for use that works with .NET?
Episerver does not have this out of the box so you normally use a third party component for.NET.
If you already have a similar page in html, aim for one that convert html to pdfs.
If you don't, or want complete control over exact formatting, use one that let's you build the pdfs piece by piece in.NET.
For advanced purposes if you need to create lots of material like product sheets it might be worth checking out the addon
As Daniel says, PDF is not built in. We usually use http://www.evopdf.com/
This is an approach with content channels, looks fun: