Single file template

<?php
/**
 * Template part for displaying posts.
 *
 * @package My Theme
 */

?>

<article id="post-<?php esc_attr(the_ID()); ?>" <?php esc_attr(post_class()); ?>>

    <?php if ( has_post_thumbnail() ) { ?>

            <div class="post-thumbnail">
                <a href="<?php esc_url(the_permalink()); ?>">
                    <?php the_post_thumbnail('stag-blog-thumbnail'); ?>
                </a>
            </div><!--end post-thumbnail-->
    <?php } ?>
    <header class="entry-header">

        <?php if(!is_single()) { ?>
            <?php the_title( sprintf( '<h2 class="entry-title"><a href="%s" rel="bookmark">', esc_url( get_permalink() ) ), '</a></h2>' ); ?>
        <?php } ?>

    </header><!-- .entry-header -->

    <div class="entry-content">
        <?php
            the_content(esc_html__('Continue Reading', 'stag'));
        ?>
    </div><!-- .entry-content -->

</article><!-- #post-## -->