OP, do you have a place where you can look at all of the files and folders on your server? It's probably called "file manager" in your cpanel or something like that.
Go to the public_html or www folder. Look for an index.html or index.php file. That's what your website loads by default when it tries to run your website. It looks like the code line:
<?php phpinfo() ?>
Is somewhere in that file. It needs to be removed. But as the other poster pointed out, you probably did the installation slightly wrong and put it in the wrong folder for your website to run properly.
Hope that helps.