page: /shop/address

<template id="address" name="Delivery Address Management"

inherit_id="website_sale.address">

<xpath expr="//label[@for='name']/.." position="before">

<div class="clearfix" />

<div class="form-group col-md-12">

<label for="drop_shipping_customer">

<input type="checkbox" name="drop_shipping_customer" value="false" onchange="if(this.checked) this.value='true'; else this.value='false';" />

Drop Shipping Customer

</label>

</div>

</xpath>

</template>

page: /shop/checkout    ( two different pages has checkboxes )

<template id="address_kanban" name="Delivery Kanban address"

inherit_id="website_sale.address_kanban">

<xpath expr="//t[@t-esc='contact']" position="after">

<label for="drop_shipping_customer">

<input type="checkbox" name="drop_shipping_customer" onchange="alert(this.checked)"/>

Drop Shipping Customer

</label>

</xpath>

</template>