Not a phone line and not an app. A call in the browser, answered at once, with the lead and a summary waiting for you.
The call happens in the browser. Afterwards you get the lead and a summary of what was discussed.
Press "Talk to us" at the bottom of this page and have the conversation yourself. Same build we would put on your site.
None of that is in a tutorial. You find it by answering your own enquiries with it.