Failed transactions in Magento 2 payment methods are handled through clear status updates and system logs. When a payment fails, the order is usually marked as failed or pending. Customers see an error message and can try the payment again using the same or a different method. Magento also records failed transaction details in logs. Magento 2 payment methods helps store owners review the reason, such as payment denial or network issues. Admins can contact customers if needed and take action without losing order data.