fabricsamples_order_form.xml

<?xml version="1.0"?>
<layout xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
  <container name="fabric.order" htmlClass="fabric-order" htmlTag="div">
    <block class="Magento\Directory\Block\Data" name="fabric.order.form" template="Graham_FabricSamples::order-form.phtml">

      <block name="fields.prefix" class="Graham\Marketing\Block\Prefix" template="Graham_Theme::form/prefix.phtml"/>
      <block name="fields.firstname" template="Graham_Theme::form/firstname.phtml"/>
      <block name="fields.lastname" template="Graham_Theme::form/lastname.phtml"/>
      <block name="fields.telephone" template="Graham_Theme::form/telephone.phtml"/>
      <block name="fields.mobile" template="Graham_Theme::form/mobile.phtml"/>
      <block name="fields.email" template="Graham_Theme::form/email.phtml"/>
      <block name="fields.street" template="Graham_Theme::form/street.phtml"/>
      <block name="fields.city" template="Graham_Theme::form/city.phtml"/>
      <block name="fields.region_id" template="Graham_Theme::form/region_id.phtml"/>
      <block name="fields.country" class="Magento\Directory\Block\Data" template="Graham_Theme::form/country.phtml"/>
      <block name="fields.postcode" template="Graham_Theme::form/postcode.phtml"/>

      <block name="marketing.email" template="Graham_Marketing::marketing/email.phtml" />
      <block name="marketing.third-party" template="Graham_Marketing::marketing/third-party.phtml" />
      <block name="marketing.catalogue" template="Graham_Marketing::marketing/catalogue.phtml" />
      <block name="marketing.opt-out-message" template="Graham_Marketing::marketing/opt-out-message.phtml" />

    </block>
  </container>
</layout>

Form.php

<?php

namespace Graham\FabricSamples\Controller\Order;
use Magento\Framework\App\Action\Action;
use Magento\Framework\App\ResponseInterface;
use Magento\Framework\Controller\ResultFactory;

class Form extends Action
{
    /**
     * Dispatch request
     *
     * @return \Magento\Framework\Controller\ResultInterface|ResponseInterface
     * @throws \Magento\Framework\Exception\NotFoundException
     */
    public function execute()
    {
        return $this->resultFactory->create(ResultFactory::TYPE_LAYOUT);
    }
}