Creating custom user registration form sometimes can be a little tricky, but lets try to create a custom registration form in Drupal 7 with just a few steps.
First we add a few lines of codes to template.php as follows
function themename_theme($existing, $type, $theme, $path){
$hooks['user_register_form']=array(
'render element'=>'form',
'template' =>'templates/user-register',
);
return $hooks;
}
function themename_preprocess_user_register(&$variables) {
$variables['form'] = drupal_build_form('user_register_form', user_register_form(array()));
}
Then creating the user-register.tpl.php and place it inside templates folder in your theme, write the following in your user-register.tpl.php:
<?php
print render($form['form_id']);
print render($form['form_build_id']);
print render($form['account']['name']);
print render($form['account']['mail']);
print render($form['field_yourcustomfield']); // Your Drupal 7 profile field if any.
print drupal_render($form['actions']);
?>
Clear your Drupal cache and visit your user registration form to see the changes.