You can use the .htaccess file to redirect visitors to different files, either on the same website, or on a different site.
Redirect rules are written as below, starting with Redirect, then the location you are directing away from, then the location you are redirecting to.
Redirect /oldindex.php /newindex.php
You can redirect whole directories as well.
Redirect /olddirectory /newdirectory
And you can redirect to a different site.
Redirect /index.php http://othersite.com/newindex.php