insert php script in header phone info

Hi,

I wrote a little php script for a website.
I want to let it show in the header phone info.
But when I insert it it doesn’t get converted to the echo’s I said (it shows the complete php code). How can I solve this?

This is my php code:

<?php
$datum = date(‘M d Y’);

switch ($datum) {
case “May 30 2018”:
echo ‘Same answer’;
break;
case “May 21 2018”:
echo ‘Same answer’;
break;
case “Jun 10 2019”:
echo ‘Same answer’;
break;
case “Aug 8 2018”:
echo ‘Same answer’;
break;
case “Dec 25 2018”:
echo ‘Same answer’;
break;
case “Dec 26 2018”:
echo ‘Same answer’;
break;
default:
echo ‘Other answer’;
}
?>