hi, how can we configure the plesk as a subdomain
for example http://plesk.domain.com instead of https://www.domain.com:8443

you could try screwing with the rewrite rules and the httpd.conf...

all i do is this

create your skeleton file with a directory called plesk inside of it.

so www.domain.com/plesk would do the trick.

in the plesk directory create a index.php file that looks exactly as i will paste.

header("Location: https://www.domain.tld:8443");
exit();
?>

that solves my issue allowing my clients to use
www.domain.tld/plesk and they get redirected to plesk

Best regards,

but my aim is to discard to usage of port numbers as 8443
because many of my clients has firewalls which is gone from government
so they have not permission to configure it

I don't believe you'll be able to do that. Sounds like your customers need to do their site admin from home instead of work.

then do your own panel using the plesk api, you can do it, it is just a matter of knowing how to do it.

Plesk has a built in package called Plesk CLI
ftp://download1.sw-soft.com/Plesk/Plesk7....unix/index.html

go for it and do your own control panel based on plesk

regards,