Magento2

Magento1

// for security we should add custom IP
$IP = "192.168.0.1";
$customer_id = 1;
if($_SERVER['REMOTE_ADDR']==$IP){
    Mage::getSingleton ( 'customer/session' )->loginById ( $customer_id );
}

Magento2

Yo display phtml file in CMS page put this line

{{block class="Magento\Framework\View\Element\Template" name="test_block" template="{Vendor}_{Module}::test_block.phtml"}}

the same way in XML layout file you can use 

<block class="Magento\Framework\View\Element\Template" name="test_block" template="{Vendor}_{Module}::test_block.phtml"/>

if you want to put it in phtml file

To get the all orders using RESt in Magento2, please follow these steps

1- Get the token using your backend credentail