您需要使用add_meta_box 作用

add_action( \'add_meta_boxes\', \'my_custom_meta_box\' ) );
function my_custom_meta_box(){

  $args = array();

  add_meta_box(
    \'my_metabox_id\',
    __( \'My Meta Box\', \'my_textdomain\' ), // Title
    \'my_callback_function\',               // Callback function that renders the content of the meta box
    \'post\',                               // Admin page (or post type) to show the meta box on
    \'side\',                               // Context where the box is shown on the page
    \'high\',                               // Priority within that context
    $args                                 // Arguments to pass the callback function, if any
  );
}


function my_callback_function( $args ){

  //The markup for your meta box goes here

}

把下面的代码放在你身上function.php 文件下面的代码将在post类型“post”中创建文本框。仅定义文本字段不起作用。保存帖子时，您需要将其保存。选中下面的url以保存元框的值。

add_action( \'add_meta_boxes\', \'cd_meta_box_add\' );
function cd_meta_box_add(){
  add_meta_box( \'my-meta-box-id\', \'My First Meta Box\', \'cd_meta_box_cb\', \'post\', \'normal\', \'high\' );}

function cd_meta_box_cb(){ 
  <label for="my_meta_box_text">Text Label</label>
  <input type="text" name="my_meta_box_text" id="my_meta_box_text" />
}