adjust page size

Hi:

New to WP – working on site and would like to make adjustment to page size so that what I am trying to view in the page does not have to be scrolled –

Dont need to adjust all pages – just a couple – or is it best to just make all pages the larges size needed?

Please see: https://printinktoner.com/wp/?page_id=321

I am trying to fit this into the page – it is an iframe of another database/server.

Thanks!