This article will give you example data format for a new modified phone call that is received and a POST request as JSON sent to your webhook URL.

{
  "trigger": "new",
  "lead_id": 153928,
  "user_id": "51497-af17340d-62b8-3044-423f-3dc754e621c2",
  "lead_type": "Phone Call",
  "lead_status": "Unique",
  "date_created": "2016-02-01T14:09:01Z",
  "quotable": "Not Set",
  "quote_value": null,
  "sales_value": null,
  "profile": "My Profile",
  "profile_id": 51497,
  "account_id": 27313,
  "lead_url": "https://www.whatconverts.com/contact",
  "landing_url": "https://www.whatconverts.com/",
  "operating_system": "iOS 12",
  "browser": "Chrome Mobile 71",
  "device_type": "Smartphone",
  "device_make": "Apple iPhone",
  "call_status": "Modified",
  "phone_name": "Google AdWords",
  "tracking_number": "+17044486577",
  "destination_number": "+17045436123",
  "caller_number": "+18033861858",
  "caller_name": "WHATCONVERTS",
  "caller_city": "Charlotte",
  "caller_state": "NC",
  "caller_zip": "28226",
  "caller_country": "US",
  "line_type": "Landline",
  "additional_fields": {
    "menu_1": "Sales",
  },
  "lead_source": "google",
  "lead_medium": "cpc",
  "lead_campaign": "lead generation",
  "lead_content": "new ad",
  "lead_keyword": "generating leads",
  "ip_address": "107.210.21.188",
  "field_mappings": {
    "Company Name": "Call Tracking Company",
    "Contact Person": "Jeremy Helms",
    "Email": "support@whatconverts.com",
    "Phone Number": "(704) 469-5324"
  },
  "gclid": "CLibmtmqpNICFcSfGwodQbUAvg",
  "msclkid": "25d83debf85f146b8f1d66a754c6a56c",
  "unbounce_page_id": "f8e32bbc-e1a1-2c5b-b4d3-c6289c8e33b",
  "unbounce_variant_id": "b",
  "unbounce_visitor_id": "107.210.21.1881565955056416071",
  "salesforce_user_id": "15228103840",
  "duplicate": false,
  "spam": false
}

For additional information on setting up webhooks see Webhooks.