Hi @Rae6 
Store is password protected, always remember to check resources as another person would see them, such as by using private browsing modes , or different devices/browsers.
https://community.shopify.com/c/blog/how-to-get-support-from-the-community/ba-p/1399408
That form is it’s own form, the cart form is it’s own form.
If an app doesn’t specifically say something like “integrates with cart form” “make form required for checkout” etc etc there is no reason to assume it can automatically interoperate other systems if at all even with theme customizations. i.e. the apps form may be in an iframe, or not provide any way to programmatically signal on the frontend when the form is submitted such as through form events.
You may need to gather this information as part of the cart form itself through advanced theme customizations:
https://community.shopify.com/topic/613718
If you need this explored as a theme customization then contact me for services.
Contact info in forum signature.
ALWAYS please provide context, examples: store url, theme name, post url(s) , or any further detail in ALL correspondence.