how to enable php on a subdomain?

Link

when i’m using the

“www . website . com”

php codes are working but when i’m using it on a subdomain the php script won’t work

“secure . website . com”

how can i enable the use of php code on my subdomain?
i’m using justhost as my server.

my subdomain is located at
/public_html/secure <–folder directory

but when i put the files inside the folder,
php scripts won’t work.
how can i enable php scripts inside my folder?

<?php
phpinfo();
?>

says it’s not supported?

justhost said to contact a php developer regarding this issue that is just what i’m doing.