how to use wp_editor() here am getting empty result

Your syntax for passing the settings array is incorrect and also you have not specified the name for the textarea in the settings array which is why it returns you an empty alert.

Syntax from WordPress Codex:

wp_editor( $content, $editor_id, $settings = array() );

$content (string) (required) – Initial content for the editor

$editor_id (string) (required) – HTML id attribute value for the textarea and TinyMCE.

$settings (array) (optional) – associative array of the keywords and their values.

And the correct code in your case should be like below. Considering that the “post_content” is the initial string that you want in your editor.

wp_editor( post_content, 'mailling_messenger1', array( 'textarea_name' => 'mailling_messenger1') );