Can you add a sheet/page of information (ideally dropdown or collapsible) to a Form?

You can use Section Collapse fields for that. This hides/shows a section of your form, and splits your form into expandable parts.

Here's a quick demo:

Here's a demo form: https://form.jotform.com/210752352570046

RELATED GUIDE: show-or-hide-multiple-fields-at-once-using-the-section-collapse-field