Use WP_Query to Create Pagination in WordPress

Custom Query

<?php
/**
* Template Name: Custom Page
*/
get_header(); ?>

<?php
$paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
$args = array(
  'posts_per_page' => 4,
  'paged' => $paged
);
$custom_query = new WP_Query( $args );
?>
          <!----start-------->
<div class="wrap">
<div id="primary" class="content-area">
<main id="main" class="site-main" role="main">

<?php
   while($custom_query->have_posts()) :
      $custom_query->the_post();
?>
       <div>
        <ul>
         <li>
           <h3><a href="<?php the_permalink(); ?>" ><?php the_title(); ?></a></h3>
        <div>
          <ul>
        <div><a href="<?php the_permalink(); ?>"><?php the_post_thumbnail('thumbnail'); ?></a></div>
          </ul>
          <ul>
        <p><?php echo the_content(); ?></p>
          </ul>
        </div>
        <div>
          </li>
        </ul>
          </div> <!-- end blog posts -->
       <?php endwhile; ?>
      <?php if (function_exists("pagination")) {
          pagination($custom_query->max_num_pages);
      } ?>
</main><!-- #main -->
</div><!-- #primary -->
</div><!-- .wrap -->
          <!----end-------->
<?php get_footer();

Pagination Function

function pagination($pages = '', $range = 4)
{
    $showitems = ($range * 2)+1;

    global $paged;
    if(empty($paged)) $paged = 1;

    if($pages == '')
    {
        global $wp_query;
        $pages = $wp_query->max_num_pages;
        if(!$pages)
        {
            $pages = 1;
        }
    }

    if(1 != $pages)
    {
        echo "<div class=\"pagination\"><span>Page ".$paged." of ".$pages."</span>";
        if($paged > 2 && $paged > $range+1 && $showitems < $pages) echo "<a href='".get_pagenum_link(1)."'>&laquo; First</a>";
        if($paged > 1 && $showitems < $pages) echo "<a href='".get_pagenum_link($paged - 1)."'>&lsaquo; Previous</a>";

        for ($i=1; $i <= $pages; $i++)
        {
            if (1 != $pages &&( !($i >= $paged+$range+1 || $i <= $paged-$range-1) || $pages <= $showitems ))
            {
                echo ($paged == $i)? "<span class=\"current\">".$i."</span>":"<a href='".get_pagenum_link($i)."' class=\"inactive\">".$i."</a>";
            }
        }

        if ($paged < $pages && $showitems < $pages) echo "<a href=\"".get_pagenum_link($paged + 1)."\">Next &rsaquo;</a>";
        if ($paged < $pages-1 &&  $paged+$range-1 < $pages && $showitems < $pages) echo "<a href='".get_pagenum_link($pages)."'>Last &raquo;</a>";
        echo "</div>\n";
    }
}

Reference: https://www.wpblog.com/use-wp_query-to-create-pagination/