// $params has the authorization headers in it
$params = wp_fusion()->crm->get_params();

// This is the data for the new company
$data = array(
    'Company_Name'  => 'Cool company',
    'Another_Field' => 'More data'
);

$params['body'] = json_encode( array( 'data' => array( $data ) ) );

$request = wp_fusion()->crm->api_domain . '/crm/v2/Companies';
$response = wp_remote_post( $request, $params );

// Check for any errors and display them if encountered
if( is_wp_error( $response ) ) {
    wp_die( $response->get_error_message() );
}

$response = json_decode( wp_remote_retrieve_body( $response ) );

$company_id = $response->data[0]->details->id;