Add paypal button to order history

In payment section, i will use Pay Invoice. My customer will get final price on invoice before made a payment. then in order history will appear the previous transaction (as per attach) i want every each order have payment button ( as per picture) 

how to i edit the coding for running the service. 

regards

You would have to edit the template file pages/order_history.inc.php. You can access the complete order object using:

$o = reference::order($order['id']);

Then access data like:

$o->payment_due;

Hi Tim, i'm not very clear for this. Here i attach what i'm done with code and the place i paste. and the result after that.

public_html>Templates>default.catalog>page>order_history.inc.php

You are showing indications that you definately don't know what you are doing. I assume you copy and pasted some general example code thinking that might do the specific job for you? You can't stick a html, head, body inside a current body. And the example code already have a non unique button placeholder.

Have a friend or freelancer to assist you. This is the best advice I can think of. For the sake of your own and your customers' security.