the_post_navigation example

get_header();

/* Start the Loop */
while ( have_posts() ) :
    the_post();

    get_template_part( 'template-parts/content/content-single' );

    if ( is_attachment() ) {
        // Parent post navigation.         the_post_navigation(
            array(
                /* translators: %s: Parent post link. */
                'prev_text' => sprintf( __( '<span class="meta-nav">Published in</span><span class="post-title">%s</span>', 'twentytwentyone' ), '%title' ),
            )
        );
    }

    // If comments are open or there is at least one comment, load up the comment template.     if ( comments_open() || get_comments_number() ) {
        comments_template();
    }