I'm getting problem on my small Apache web server.

I'm doing URL sending at domain controller user interface. Say our client typing the domain xxx.com and it'll redirect to 123.456.789.10/www (my webserver fix ip). Our client browser will shows 123.456.789.10/www on their own browser rather than showing xxx.com.

Is almost anything to do in order to my Apache setting or how to pull off it? It appears strange to exhibit my client the ip rather than the domain title.

You need to set a b record inside your DNS registration to suggest the main domain title (@) for your Ip.
(and most likely an identical An archive for that www host)

You may want to configure the net server to reply to that hostname.