composer require mediatoolkit/activecampaign-v3-php

$client = new Client(
    $api_url, 
    $api_token, 
    $event_tracking_actid, 
    $event_tracking_key
);

$contacts = new Contacts($client);

$contact = $contacts->create([
    'email' => 'CONTACT_EMAIL',
    'firstName' => 'CONTACT_FIRST_NAME',
    'lastName' => 'CONTACT_LAST_NAME'
]);