eiru_sale_order/static/src/xml/sale_order.xml

<?xml version="1.0" encoding="UTF-8"?>
<template xml:space="preserve">
    <t t-name="eiru_sale_order.SaleOrder">
        <div class="ui-widget col-md-6 col-md-offset-3">
        	<div class="form-group">
        		<label for="productSearch">Buscar: </label>
		  		<input id="productSearch" class="form-control"/>
        	</div>
		</div>
    </t>
</template>