magento-test/app/code/Magento/Sales/Test/Mftf/ActionGroup/OrderSelectFlatRateShippingActionGroup.xml

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

<actionGroups xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:mftf:Test/etc/actionGroupSchema.xsd">
    <actionGroup name="OrderSelectFlatRateShippingActionGroup">
        <annotations>
            <description>Selects the 'Flat Rate' Shipping Method on the Admin 'Create New Order for' page.</description>
        </annotations>

        <click selector="{{AdminOrderFormPaymentSection.header}}" stepKey="unfocus"/>
        <waitForLoadingMaskToDisappear stepKey="waitForJavascriptToFinish"/>
        <click selector="{{AdminOrderFormPaymentSection.getShippingMethods}}" stepKey="clickShippingMethods"/>
        <waitForElementVisible selector="{{AdminOrderFormPaymentSection.flatRateOption}}" stepKey="waitForShippingOptions"/>
        <selectOption selector="{{AdminOrderFormPaymentSection.flatRateOption}}" userInput="flatrate_flatrate" stepKey="checkFlatRate"/>
    </actionGroup>
</actionGroups>