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>
        <newsletter>
            <general>
                <active>1</active>
            </general>
            <subscription>
                <allow_guest_subscribe>1</allow_guest_subscribe>
                <confirm>0</confirm>
                <confirm_email_identity>support</confirm_email_identity>
                <confirm_email_template>newsletter_subscription_confirm_email_template</confirm_email_template>
                <success_email_identity>general</success_email_identity>
                <success_email_template>newsletter_subscription_success_email_template</success_email_template>
                <un_email_identity>support</un_email_identity>
                <un_email_template>newsletter_subscription_un_email_template</un_email_template>
            </subscription>
            <sending>
                <set_return_path>0</set_return_path>
            </sending>
        </newsletter>
    </default>
</config>