You dont need HTML tags in this file coz you are just saving some variables.... something like this might work for you
Say you have a HTML form that POSTs username and password fields to config.php at the time of installation
config.php
$acname = $_POST['username'];
$pass = $_POST['password'];
$fname = fopen("storepass.php","wt");
fwrite($fname,"\$username=\"$acname\"\n");
fwrite($fname,"\$password=\"$pass\"\n");
fclose($fname);
now you have storepass.php in which you have variable $username and $password
Include them where ever you need username and pass... say u got another code where u want access DB with these username and pass...
somefile.php
include("storepass.php");
mysql_connect("localhost", "$username", "$password");
....
...
There might be some syntax errors.. with escape characters.. so take a look at config.php 😉
Have Fun!
TommYNandA