Customize Tiny MCE (Paragraph Indent)

add-to-functions.php

//Custom Text Formatting Options
function wpb_mce_buttons_2($buttons) {
	array_unshift($buttons, 'styleselect');
	return $buttons;
}
add_filter('mce_buttons_2', 'wpb_mce_buttons_2');


/*
* Callback function to filter the MCE settings
*/

function my_mce_before_init_insert_formats( $init_array ) {  

// Define the style_formats array

	$style_formats = array(  
		// Each array child is a format with it's own settings
		array(  
			'title' => 'Indented Text',  
			'selector' => 'p,h1,h2,h3,h4,h5,h6',  
			'classes' => 'entry-content-indented',

			
		),  

	);  
	// Insert the array, JSON ENCODED, into 'style_formats'
	$init_array['style_formats'] = json_encode( $style_formats );  
	
	return $init_array;  
  
} 

// Attach callback to 'tiny_mce_before_init' 
add_filter( 'tiny_mce_before_init', 'my_mce_before_init_insert_formats' );