I moved your question to its own thread. If you have questions, don’t post them in someone else’s threads, but start a new one please. And if your question is related to someone else’s, link to that other thread.
Have you checked to be sure you have PHP available for your site? I expect most web hosting now includes PHP, but that is something to check.
If you are sure you have PHP, try renaming your index page index.php. Unless you do something via .htaccess, you need to name your pages with the php extension.
The path to the include file should be relative to the folder containing the file the include statement is in.
Is banner.php in the same folder as the file containing the include statement is in? If not, specify the relative path to banner.php in your include().
And like CSU-Bill says, your files with php code in them should have a php extension in their file names.
Its pretty easy to test what webdev1958 says, put these 2 files into the same folder.
banner.php
<?php
echo "<p>Banner.php says Hello!</p>";
?>
test.php
<p>This is basic html which did not need PHP ...</p>
<?php
echo "<p>PHP says Hello!</p>";
if( include 'banner.php' ){
$include_path = ini_get("include_path");
echo '<p>You could also move banner.php to any of these folders and it should work : ' . $include_path . '</p>';
}
?>