AddHandler application is not inherited

Ubuntu Linux 20.04.2
Virtualmin version 6.16

To execute php codes in html files, I added
“AddHandler application/x-httpd-php7.4 .html .htm” to
virtualmin-services-configure website-edit directives.

It works, but the rule is not inherited in subdirectories. Is there a way to make these settings applicable in all subdirectories?

Thank you