Add action to contact form?

Hi,

Apologies if the following has been asked/answered before. A quick search didn’t give me related results.

We’re using a third-party application to capture filled in contact form information. At the moment the contact form is created in that application and shown on the website through an iframe. As I absolutely despise unnecessary iframes, I would prefer to create forms inside WP and just send the info to the third-party app.

But, in order to do so we need to add some action to the form. Apparently there isn’t an option in the page builder, so now I ask:
Is there any way of adding an action through the debug mode, for example, or any other way? If not, is there any plugin you may know of that supports this without causing conflicts with Enfold?

Thanks in advance for your feedback.