Quick Snippet to display Wordpress Categories.

categories.php

<?php
  $getCategoriesArgs = array('orderby' => 'name','parent' => 0);
	$getCategories = get_categories($getCategoriesArgs);
	if(count($getCategories) > 0){
		echo '<ul>';
		foreach ( $getCategories as $category ) {
			echo '<li><a href="'.get_category_link($category->term_id).'">'.$category->name.'</a></li>';
		}
		echo '</ul>';
	}
?>