config.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
    <default>
        <cataloginventory>
            <source_selection_distance_based>
                <provider>google</provider>
            </source_selection_distance_based>
            <source_selection_distance_based_google>
                <mode>driving</mode>
                <value>distance</value>
                <api_key></api_key>
            </source_selection_distance_based_google>
        </cataloginventory>
    </default>
</config>