HI I'm having two wesites with same file sets
I want to keep the one file set for both domains how to do this
if the user visit
www.abc.com the files will get from

kindly tell me how to do this
one thing i don't want to keep file set in both side

So, based on your description, you want the behaviour as follows: If a user visits www.abc.com, or www.xyz.com, you would like the user to access the xzy.com website? Correct?

The first step is to set up your DNS records properly. If you manage the abc.com zone, log into your DNS management console and udate the "www" record to point to the IP address of the webserver hosting the xyz.com site.

The next step is to configure your web server/web site properly.

Is this web site hosted? If so, log into the web admin console/panel and configure the site to accept traffic for both domains. If you need help with this part, your hosting provider most likely has documentation on how to do this. While the concept is the same, each provider may have a different console so the steps would be slightly different.

In addition, if you want the URL in the address bar to read www.xyz.com when the user types www.abc.com, you'll need to configure your web site to perform the appropriate redirection. If the URL is not important, the steps above should be sufficient.