system.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_Config:etc/system_file.xsd">
    <system>
        <section id="sales">
            <group id="instant_purchase" translate="label" type="text" sortOrder="200" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Instant Purchase</label>
                <field id="active" translate="label comment" type="select" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
                    <label>Enabled</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                    <comment>Payment method with vault and instant purchase support should be enabled.</comment>
                </field>
                <field id="button_text" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
                    <label>Button Text</label>
                </field>
            </group>
        </section>
    </system>
</config>