How To Configure User Registration Form?

Hello, I want to create a checkbox that when clicked, will show two additional fields in the registration form. I can create the checkbox itself from Administration/Profile fields, but there is no way of implementing a described functionality from there and I'm assuming it's only possible from the code.

Where in code is the registration implemented? Is there any registration tpl hook that I can use?

You should use hooks in the following template

design/themes/THEME/templates/views/profiles/components/profile_fields.tpl

Thank you, it works!

I'm new to cs-cart is any way of finding out which template contains given element? For example when I see an input field somewhere on the site, is there a way to easily check by which .tpl file it was created? I'm really struggling with it right now.

Thank you, it works!

I'm new to cs-cart is any way of finding out which template contains given element? For example when I see an input field somewhere on the site, is there a way to easily check by which .tpl file it was created? I'm really struggling with it right now.

You can try to use Templates section in the debugger

https://docs.cs-cart.com/4.7.x/developer_guide/tools/debugger.html

But it is not quite clear

The debugger will help point you in the right direction. Additionally, you might use the theme editor to get an idea of what element resides in which template (language editor). Most of the tools work at the file level, not at the data level.