magento-test/app/code/Magento/Sales/Test/Mftf/Section/AdminSalesOrderCommentsSection.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
 /**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-->

<sections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:mftf:Page/etc/SectionObject.xsd">
    <section name="AdminSalesOrderCommentsSection">
        <element name="historyComment" type="textarea" selector="#history_comment"/>
        <element name="historyVisible" type="checkbox" selector="#history_visible"/>
        <element name="submitOrderComment" type="button" selector=".order-history-comments-actions>button"/>
    </section>
</sections>