Customize TinyMCE in WP

// add style selector drop down 
function my_mce_buttons_2( $buttons ) {
    array_unshift( $buttons, 'styleselect' );
    return $buttons;
}

add_filter( 'mce_buttons_2', 'my_mce_buttons_2' );

// customize the MCE editor
function aah_customize_mce( $init ) {
    /* Only include these tags */
    $init['theme_advanced_blockformats'] = 'h2,h3,h4,p';
    /* Remove these buttons */
    $init['theme_advanced_disable'] = 'forecolor, underline, justifyfull, indent, outdent'; /*

    /* Set up your custom style classes */
    $style_formats = array(
      array(
        'title' => 'Intro Paragraph',
        'selector' => 'p',
        'classes' => 'lead'
      ),
    );

    /* Only include your custom styles -- defined above -- in your style dropdown */
    $init['style_formats'] = json_encode( $style_formats );
    return $init;
}
 
add_filter('tiny_mce_before_init', 'aah_customize_mce');