execute PHP code on a .html
page is to modify your .htaccess file. This file may be hidden, so depending upon your FTP program you may have to modify some settings to see it. Then you just need to add this line for .html file
AddType application/x-httpd-php .html
Or for .htm file
AddType application/x-httpd-php .htm
If you only plan on including the PHP on one page, it is better to setup this way:
<Files yourpage.html> AddType application/x-httpd-php .html </Files>
This code will only make the PHP executable on the yourpage.html file, and not on all of your html pages.