use $_POST['name'] - you've probably got globals off in php.ini
and just checking but you'll need a submit button too :
<input type="submit" value="submit">
amd you should reall be using echo too, and you have to break out of the echo to print the array:
echo "Welcome ".$_POST['name'];
and its not a bad idea to use a better, more relevant title than just "help" in the future too.