How to add a “Who’s who” on a wordpress blog post?

by

You can add this to your single

the_author_posts_link();

But, you can use plugin for author box if
you want to do it more simple and had more options like put the social
links, website links, even the gravatar.

and for the author page, it will use this template.

  1. author-{nicename}.php – If the author’s nice name were rami, WordPress would look for 2. author-rami.php.
  2. author-{id}.php – If the author’s ID were 6, WordPress would look for author-6.php.
  3. author.php
  4. archive.php
  5. index.php

this is the sample of author template

<?php get_header(); ?>

<div id="content" class="narrowcolumn">

<!-- This sets the $curauth variable -->

    <?php
    $curauth = (isset($_GET['author_name'])) ? get_user_by('slug', $author_name) : get_userdata(intval($author));
    ?>

    <h2>About: <?php echo $curauth->nickname; ?></h2>
    <dl>
        <dt>Website</dt>
        <dd><a href="<?php echo $curauth->user_url; ?>"><?php echo $curauth->user_url; ?></a></dd>
        <dt>Profile</dt>
        <dd><?php echo $curauth->user_description; ?></dd>
    </dl>

    <h2>Posts by <?php echo $curauth->nickname; ?>:</h2>

    <ul>
<!-- The Loop -->

    <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
        <li>
            <a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link: <?php the_title(); ?>">
            <?php the_title(); ?></a>,
            <?php the_time('d M Y'); ?> in <?php the_category('&');?>
        </li>

    <?php endwhile; else: ?>
        <p><?php _e('No posts by this author.'); ?></p>

    <?php endif; ?>

<!-- End Loop -->

    </ul>
</div>
<?php get_sidebar(); ?>
<?php get_footer(); ?>

source:

https://codex.wordpress.org/Author_Templates