В файле
checkout_index_index.xml(Module, Theme, etc) нужно изменить
sortOrder у
shipping-step и
billing-step.
Пример:
Magento/Checkout/view/frontend/layout/checkout_index_index.xml
checkout_index_index.xml :
<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceBlock name="checkout.root">
<arguments>
<argument name="jsLayout" xsi:type="array">
<item name="components" xsi:type="array">
<item name="checkout" xsi:type="array">
<item name="children" xsi:type="array">
<item name="steps" xsi:type="array">
<item name="children" xsi:type="array">
<item name="billing-step" xsi:type="array">
<item name="sortOrder" xsi:type="string">1</item>
</item>
<item name="shipping-step" xsi:type="array">
<item name="sortOrder" xsi:type="string">2</item>
</item>
</item>
</item>
</item>
</item>
</item>
</argument>
</arguments>
</referenceBlock>
</body>
</page>