Why is not my custom checkout field sent to the server?

Hi,
I added custom field to checkout shipping address with checkout_index_index.xml file:

    <?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" layout="1column" 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="shipping-step" xsi:type="array">
                                            <item name="children" xsi:type="array">
                                                <item name="shippingAddress" xsi:type="array">
                                                    <item name="children" xsi:type="array">
                                                        <item name="shipping-address-fieldset" xsi:type="array">
                                                            <item name="children" xsi:type="array">
                                                                <item name="regulation" xsi:type="array">
                                                                    <item name="component" xsi:type="string">Magento_Ui/js/form/element/boolean</item>
                                                                    <item name="config" xsi:type="array">
                                                                        <!--customScope is used to group elements within a single form (e.g. they can be validated separately)-->
                                                                        <item name="customScope" xsi:type="string">shippingAddress</item>
                                                                        <item name="template" xsi:type="string">ui/form/field</item>
                                                                        <item name="elementTmpl" xsi:type="string">ui/form/element/checkbox</item>
                                                                    </item>
                                                                    <item name="provider" xsi:type="string">checkoutProvider</item>
                                                                    <item name="dataScope" xsi:type="string">shippingAddress.regulation</item>
                                                                    <item name="label" xsi:type="string">Checkbox Field</item>
                                                                    <item name="sortOrder" xsi:type="string">300</item>
                                                                </item>

                                                            </item>
                                                        </item>
                                                    </item>
                                                </item>
                                            </item>
                                        </item>
                                    </item>
                                </item>
                            </item>
                        </item>
                    </item>
                </argument>
            </arguments>
        </referenceBlock>
    </body>
</page>

Field displays correctly but it is not sending with other address fields. Do you know why it is not sending? And where it should save in database? I need to add field to sales_order table?
I get other address data in Request payload section.