当网站有多个类型内容的时候，可能需要用到Custom Post Type UI这个插件来分出几个post type，但是如果想要在自定义的post type的文章内容里面添加tag就需要做一下操作：

1、首先确保已安装 Custom Post Type UI插件

2、安装完插件以后进入后台CPT UI —->Import/Export，在打开的页面里面找到Get Code标签，找到对应的post type代码复制，然后放在主题目录下面的functions.php文件下面

3、 对已复制的代码进行修改：

add_action( 'init', 'cptui_register_my_cpts_application' );
function cptui_register_my_cpts_application() {
	$labels = array(
		"name" => "Applications",
		"singular_name" => "Application",
		);

	$args = array(
		"labels" => $labels,
		"description" => "",
		"public" => true,
		"show_ui" => true,
		"show_in_rest" => true,
		"has_archive" => true,
		"show_in_menu" => true,
		"exclude_from_search" => false,
		"capability_type" => "post",
		"map_meta_cap" => true,
		"hierarchical" => true,
		"rewrite" => array( "slug" => "application", "with_front" => true ),
		"query_var" => true,

		"supports" => array( "title", "editor", "excerpt", "trackbacks", "custom-fields", "comments", "revisions", "thumbnail", "author", "page-attributes", "post-formats" ),		
		"taxonomies" => array( "application-category" ),		
	);
	register_post_type( "application", $args );

// End of cptui_register_my_cpts_application()
}

替换成一下代码：

add_action( 'init', 'wpsites_custom_post_type' );
function wpsites_custom_post_type() {

register_post_type( 'application',
    array(
        'labels' => array(
            'name'          => __( 'Applications', 'wpsites' ),
            'singular_name' => __( 'Application', 'wpsites' ),
        ),
        'has_archive'  => true,
        'hierarchical' => true,
        'menu_icon'    => 'dashicons-heart',
        'public'       => true,
        'rewrite'      => array( 'slug' => 'application', 'with_front' => false ),
        'supports'     => array( "title", "editor", "excerpt", "trackbacks", "custom-fields", "comments", "revisions", "thumbnail", "author", "page-attributes", "post-formats" ),
        'taxonomies'   => array( 'application',  'post_tag' ),
    ));

}