Tinymce Advanced Style Formats Example for Wordpress. Example of using HTML5 formatting in TINYMCE Visual Editor for Wordpress taken from this example on TinyMCE's site ( link https://www.tinymce.com/docs/demo/format-html5/ ).

style-formats.php

<?php

/** 
 * HTML5 Styles Dropdown
 * 
 * @author Bryan Willis
 * @link https://www.tinymce.com/docs/demo/format-html5/
 */ 
function mce_html5_formatting( $init ) {

//$init['block_formats'] = 'Paragraph=p;Heading 1=h1;Heading 2=h2;Heading 3=h3;Heading 4=h4;Heading 5=h5;Heading 6=h6;';
    
$style_formats =array(
	array(
		'title' => 'Headers',
		'items' => array(
			array(
				'title' => 'Header 1',
				'block' => 'h1'
			) ,
			array(
				'title' => 'Header 2',
				'block' => 'h2'
			) ,
			array(
				'title' => 'Header 3',
				'block' => 'h3'
			) ,
			array(
				'title' => 'Header 4',
				'block' => 'h4'
			) ,
			array(
				'title' => 'Header 5',
				'block' => 'h5'
			) ,
			array(
				'title' => 'Header 6',
				'block' => 'h6'
			)
		)
	) ,
	array(
		'title' => 'Blocks',
		'items' => array(
			array(
				'title' => 'Paragraph <p>',
				'block' => 'p'
			) ,
			array(
				'title' => 'Arbitrary Division <div>',
				'block' => 'div'
			) ,
			array(
				'title' => 'Preformatted Text <pre>',
				'block' => 'pre'
			)
		)
	) ,
	array(
		'title' => 'Containers',
		'items' => array(
			array(
				'title' => 'Section',
				'block' => 'section',
				'wrapper' => 'true',
				'merge_siblings' => 'false'
			) ,
			array(
				'title' => 'Blockquote',
				'block' => 'blockquote',
				'wrapper' => 'true',
				'icon' => 'blockquote'
			) ,
			array(
				'title' => 'Figure',
				'block' => 'figure',
				'wrapper' => 'true'
			)
		)
	)
);

$init['style_formats'] = json_encode( $style_formats );
$init['style_formats_merge'] = false;
return $init;

	
}
add_filter('tiny_mce_before_init', 'mce_html5_formatting');



//* Move the Style Select Button First
function mce_add_buttons_styleselect( $buttons ){
	array_splice( $buttons, 1, 0, 'styleselect' );
	return $buttons;
}
add_filter( 'mce_buttons_2', 'mce_add_buttons_styleselect' );
// */