I went through some old posts in this forum on the possibility to include php code into a placeholder.

First, I published the website to my php server (a wordpress provider) and as test, I simply added <?php echo “hello world”;?> to my gallery page and renamed that to *.php on the server.

Of course this did not work, I know what I am trying is way too simplistic. But could someone give me a hint how I could get this to work ?

I've read somewhere you would need to configure two index files, one *.htm and another *.php ? Or should I rename all my files to *.php ?