Embedded Form gives Page Not Found where form should be

I embedded a form into my “WP-Package-Signup-Form” page.
I uploaded the form folder into wp-content/themes/Builder-Attent-child area in a folder called WPMaintenanceForm. On the outside of the form is: WPMaintenanceForm.php. These usually go where the actual page is (when just using HTML and PHP site. With WP, I thought putting it in the theme would work.

This is an addon website, so I could put it in that folder, but then it would not be anywhere near the page.

My code:

<script type="text/javascript">// <![CDATA[
// < ![CDATA[ document.write(unescape("%3Ciframe id=\"fb_iframe\" src=\"wp-content/themes/Builder-Attent-child/WPMaintenanceForm.php" + window.location.search + "\" width=\"100%\" height=\"1574\"allowtransparency=\"true\" scrolling=\"no\" frameborder=\"0\"%3E<a href=\"wp-content/themes/Builder-Attent-child/WPMaintenanceForm.php\" title=\"WPMaintenanceForm\">Check out my CoffeeCup Form</a>%3C/iframe%3E"));
// ]]></script>
<noscript>

<iframe id="fb_iframe" style="border: none; background: transparent; overflow: hidden; width: 100%;" src="wp-content/themes/Builder-Attent-child/WPMaintenanceForm/WPMaintenanceForm.html" width="300" height="1574">
<a href="wp-content/themes/Builder-Attent-child/WPMaintenanceForm.php" title="WPMaintenanceForm">Check out my CoffeeCup Form</a>
</iframe>
</noscript>

site: https://www.hlnwebdesigns.com

Do I need to place the folder and .php page somewhere else?
This form is not a plugin. I am using CoffeeCup Form Builder.

thanks,

Helen