I can\'t really use PHP and from what I\'ve seen in tutorials this should work, but it doesn\'t:
PHP is a server-side language, so you'll need to submit the form in order to access its variables.
Since you didn't specify a method, GET is assumed, so you'll need the $_GET super-global:
echo $_GET['name'];
It's probably better though, to use $_POST (since it'll avoid the values being passed in the URL directly. As such, you can add method attribute to your element as follows:
Notice I also added a submit button for good measure, but this isn't required. Simply hitting return inside the textbox would submit the form.