You can use a parameter for the shortcode to change the behaviour of the button. If you want to show the form directly you can use:
Not sure what you mean with “this form software”?
The website https://demo.zenoweb.nl/wordpress-plugins/gwolle-guestbook-the-add-on/ has a demo for the guestbook including some things from the addon.
This page we are typing on is BBpress, just like the support forum on wordpress.org.
The reviews on this website are the guestbook with some text strings changed, like guestbook to review.