A lead is the moment an anonymous visitor becomes a person you can follow. BrainyMetrics captures it from forms without any setup: fields are recognised by type, name, autocomplete, placeholder and label, including React forms without a form tag, open shadow DOM widgets and same-origin iframes. HubSpot, Calendly and Typeform embeds are detected through their own events.
Everything the browser did before, including the ad click that brought the person in, is attached to the new lead. A submission by someone who is already a lead counts as a repeat lead, so you can see which campaigns reach new people and which keep re-reaching your existing audience.