How to redirect to another page using PHP

You could use a function similar to:

function redirect($url) {
    header('Location: '.$url);
    die();
}

Worth noting, you should them with a die() or exit() function to prevent further code execution.

Note that it just makes no sense to output large chunks of HTML if you are going to redirect. Therefore you have to move the form handling code above all HTML. As a side effect it will mitigate the notorious "Headers already sent" error.

Here's a more detailed guide than any of the other answers have mentioned: http://www.exchangecore.com/blog/how-redirect-using-php/

This guide includes reasons for using die() / exit() functions in your redirects, as well as when to use ob_flush() vs ob_start(), and some potential errors that the others answers have left out at this point.

You can conditionally redirect to some page within a php file....

if (/*Condition to redirect*/){
  //You need to redirect
  header("Location: http://www.yourwebsite.com/user.php"); /* Redirect browser */
  exit();
 }
else{
  // do some
}