List categories with custom code

<ul>
<?php
$categories = get_categories();
foreach($categories as $category)
{
?>
<li><a href="https://wordpress.stackexchange.com/questions/165159/<?php echo get_category_link($category->cat_id);?>">$category->name</a></li>
<?php
}

?>
</ul>

Just simply change the content inside the foreach loop to output how ever your desire. If you are doing this in a number of places drop it into a function and echo the function from your functions file.

Drop this into your functions.php

<?php  
  function outputcategories()
    {
?>
       <ul>
        <?php
        $categories = get_categories();
        foreach($categories as $category)
        {
        ?>
        <li><a href="https://wordpress.stackexchange.com/questions/165159/<?php echo get_category_link($category->id);?>">$category->name</a></li>
        <?php
        }

        ?>
        </ul>
<?php
    }

then to use it run the below

<?php echo outputcategories();  ?>