<?xml version="1.0" encoding="UTF-8"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceBlock name="customer_account_navigation">
<block class="Magento\Framework\View\Element\Html\Link\Current" ifconfig="helpdesk/frontend/is_active" name="customer-account-navigation-helpdesk-link">
<arguments>
<argument name="path" xsi:type="string">helpdesk/index/index</argument>
<argument name="label" xsi:type="string">Help Desk</argument>
</arguments>
</block>
</referenceBlock>
</body>
</page>
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$eavModel = $objectManager->create('\Magento\Eav\Model\Config');
$attribute = $eavModel->getAttribute('customer', $customerAttribute);