Your documentation states:
...and the above documentation states that we can link this checkbox (Subscription Type) to a Service using the form builder) but we want to create a simple button (like a "Submit" button, NOT a checkbox)
that functions the same as a checkbox--meaning we want the user, by clicking on our form "Submit" button to opt into the Service, much like checking the checkbox opts into the Service.
But since the form builder only allows a Subscription Type (i.e., a checkbox) to be linked to a Service, we want to know if there is a way of building our "Submit" button using HTML and linking it to a Service.
So the question really is two: 1) How can we link a Service to our "Submit" button we've created using HTML
Is there another way to create a subscription to a service WITHOUT using the Subscription Type (checkbox in the form builder)?
Which HTML tag do you want to link to a service?
Does what is described in this page meet your requirements? If you specifically need the HTML, you can have a look at the code generated by this operation.
Let me know.