using a custom form

I have a form that I need to include on my website:

https://www.roastedstone.com/wp-content/themes/test/index.html

I created a Page in WP called Order Form and copy and pasted the HTML from the above form into the page. Here is the result:

https://www.roastedstone.com/orderform/

At the bottom of the page is a form field that onchange should bring up the rest of the form. but it does not.

The HTML code is copied exactly form the HTML page into the WP Page.

Does anyone have any ideas what I need to do to make the form work?

Thank you in advance,
Holly