How to include pagination in a Wordpress Custom Post Type Query

Try the code below:

    $the_query = new WP_Query( array('posts_per_page'=>30,
                                 'post_type'=>'phcl',
                                 'paged' => get_query_var('paged') ? get_query_var('paged') : 1) 
                            ); 
                            ?>
<?php while ($the_query -> have_posts()) : $the_query -> the_post(); ?>
<div class="col-xs-12 file">
<a href="<?php the_permalink(); ?>" class="file-title" target="_blank">
<i class="fa fa-angle-right" aria-hidden="true"></i> <?php echo get_the_title(); ?>
</a>
<div class="file-description"><?php the_content(); ?></div>
</div>
<?php
endwhile;

$big = 999999999; // need an unlikely integer
 echo paginate_links( array(
    'base' => str_replace( $big, '%#%', get_pagenum_link( $big ) ),
    'format' => '?paged=%#%',
    'current' => max( 1, get_query_var('paged') ),
    'total' => $the_query->max_num_pages
) );

wp_reset_postdata();

When querying a loop with new WP_Query set the 'total' parameter to the max_num_pages property of the WP_Query object.

Example of a custom query:

<?php
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

$args = array(
    'post_type'=>'post', // Your post type name
    'posts_per_page' => 6,
    'paged' => $paged,
);

$loop = new WP_Query( $args );
if ( $loop->have_posts() ) {
    while ( $loop->have_posts() ) : $loop->the_post();

             // YOUR CODE

    endwhile;

    $total_pages = $loop->max_num_pages;

    if ($total_pages > 1){

        $current_page = max(1, get_query_var('paged'));

        echo paginate_links(array(
            'base' => get_pagenum_link(1) . '%_%',
            'format' => '/page/%#%',
            'current' => $current_page,
            'total' => $total_pages,
            'prev_text'    => __('« prev'),
            'next_text'    => __('next »'),
        ));
    }    
}
wp_reset_postdata();
?>

Example of paginate_links parameters adapted to the custom query above:

For more reference please visit this link