Hi Cindy - after checking out with OPC on the checkout success page SITE/index.php?main_page=checkout_success I am seeing the following;
Checkout Success Sample Text ...

HTML Code:
Checkout Success Sample Text ...

A few words about the approximate shipping time or your processing policy for guest-checkout would be put here.

This section of text is from the Define Pages Editor located under Tools in the Admin.
You can view the status of this order by going to the Order Status page and supplying this order number and your email address.
Please direct any questions you have to customer service.
in admin/tools/define pages editor/checkout success ... I inserted customized text when the site was built but that text is not showing - have I missed a file merge or something?

cheers, Mike