Can you use the iPad trackpad to scroll up/down the page?

If you intend to use a TrackPad with your iPad, you’ll need to learn the appropriate control gestures - all of which are documented within the [often overlooked] iPad User Guide. Here is a direct link to the relevant section of the Guide:

Trackpad gestures for iPad - Apple Support

The iPad User Guide is a rich source of frequently overlooked information about your iPad and iPadOS. The full Guide is available both online using a web browser (such as Safari), or as an Apple Books download:

iPad User Guide - Apple Support

https://books.apple.com/book/id1567104892

The Tips App, installed by default on most models of iPad, provides a brief introduction - and leads you to the User Guide. In case you missed it, here is a link to the Tips App:

https://apps.apple.com/gb/app/tips/id1069509450

Generally yes, but I suppose it could depend on the application being used and the document being processed.