Hello developers,

• Here I am going to show you how to easily create custom single post templates in WordPress without plugin.
• Sometimes you want different look in your posts of your websites.
• Custom single post templates allows you to select different templates for your posts.
• Please follow my below article.
• Make copy of single.php and give it name whatever you like.
• For e.g, I have made  my-template.php file.
• Open it and copy below code in top section. Please check below code.  

<?php
/*
 * Template Name: My Template
 * Template Post Type: post
*/
get_header(); ?>

Now, copy all below content just after get_header(); ?> which is in single.php. Please check below code.

<div class="wrap">
	<div id="primary" class="content-area">
		<main id="main" class="site-main" role="main">
			<?php
			/* Start the Loop */
			while ( have_posts() ) :
				the_post();
				get_template_part( 'template-parts/post/content', get_post_format() );
				// If comments are open or we have at least one comment, load up the comment template.
				if ( comments_open() || get_comments_number() ) : 					comments_template();
				endif;
			endwhile; // End of the loop.
			?>
		</main><!-- #main -->
	</div><!-- #primary -->
	<?php get_sidebar(); ?>
</div><!-- .wrap --> 

You can see in post template in admin section and select template. You will be able to select your template. You can see in below screenshot.

Hopefully this article useful for you.

Thank You 🙂