WellCommerce\Bundle\OrderBundle\Provider\OrderModifierProviderInterface::getOrderModifier PHP Method

    public function getOrderModifier(OrderInterface $order, string $name) : OrderModifierInterface;

 /**
  * {@inheritdoc}
  */
 public function visitOrder(OrderInterface $order)
 {
     $shippingMethod = $order->getShippingMethod();
     $paymentMethods = $shippingMethod->getPaymentMethods();
     if (false === $order->hasPaymentMethod() || false === $paymentMethods->contains($order->getPaymentMethod())) {
         $order->setPaymentMethod($paymentMethods->first());
     }
     $modifier = $this->orderModifierProvider->getOrderModifier($order, 'payment_surcharge');
     $modifier->setCurrency($order->getCurrency());
     $modifier->setGrossAmount(0);
     $modifier->setNetAmount(0);
     $modifier->setTaxAmount(0);
 }