<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="shipping-step" xsi:type="array">
<item name="children" xsi:type="array">
<item name="shippingAddress" xsi:type="array">
<item name="children" xsi:type="array">
<!-- The name of the form the field belongs to -->
<item name="shipping-address-fieldset" xsi:type="array">
<item name="children" xsi:type="array">
<item name="city" xsi:type="array">
<item name="sortOrder" xsi:type="string">6</item>
</item>
<item name="region_id" xsi:type="array">
<item name="sortOrder" xsi:type="string">3</item>
</item>
<item name="region_id" xsi:type="array">
<item name="sortOrder" xsi:type="string">9</item>
</item>
<item name="postcode" xsi:type="array">
<item name="sortOrder" xsi:type="string">5</item>
</item>
<item name="country_id" xsi:type="array">
<item name="sortOrder" xsi:type="string">7</item>
</item>
<item name="lastname" xsi:type="array">
<item name="sortOrder" xsi:type="string">2</item>
</item>
<item name="firstname" xsi:type="array">
<item name="sortOrder" xsi:type="string">1</item>
</item>
<item name="company" xsi:type="array">
<item name="sortOrder" xsi:type="string">4</item>
</item>
<item name="telephone" xsi:type="array">
<item name="sortOrder" xsi:type="string">8</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</item>
</argument>
</arguments>
</referenceBlock>