If I create a placeholder for Iframe and insert the link as done in "simplgalweb" design, then upload to a server that allows php, wouldn't that work. As the HTML file within the iframe would call the PHP scripts as necessary.
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Scotty calling a *.php file or wrapping PHP code with an <iframe> tag inside a .htm file isn't going to work.

You could try using an 'include' (like this: <?php include("filename.php"); ?> )
But the file that contains that code cannot be a .htm file, it needs to be a PHP file.

What does work, but isn't really clean or proper php, is to export your site with the above code in the placeholder then rename your index.htm to index.php

This tells the server to parse your file as a php (Hypertext Pre-Processor) and any included php code.

Upload the site to a host who's server support php and test.
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