Contact form for a landing page linked to CRM?

Question

CRM

There is a landing page in HTML/CSS/PHP.
It needs a feedback form, from which the data from the site would fall into some kind of application processing system (preferably a free CRM system, etc.).
Suggest possible options, please.

Answer 1

From what I used - clientbase. There is a form builder in the admin panel. As for paying, HZ, it seems that once there were free versions with restrictions, but now I'm too lazy to look.