Wordpress Meta Fields Not Showing in Post Editor

Question

a little new to working with WP and Custom Meta Fields.

I'm trying to learn REST API and created a plugin to register a custom metafield. This is the plugin:

/**
 * @package api_testing
 * @version 1.0.0
 */
/*
Plugin Name: API Testing
Plugin URI: http://example.com/
Description: The beginning of an awesome plugin
Author: Me
Version: 1.0.0
Author URI: http://example.com/
*/

function generate_press_type() {
    $labels = array(
        'name'                  => 'Press Articles',
        'singular_name'         => 'Press',
    );
    $args = array(
        'label'                 => 'Press',
        'labels'                => $labels,
        'supports'              => array( 'title', 'editor', 'custom-fields', 'thumbnail' ),
        'taxonomies'            => array( 'category', 'post_tag' ),
        'hierarchical'          => false,
        'public'                => true,
        'capability_type'       => 'post',
        'show_in_rest'          => true,
        'rest_base'             => 'press-articles',
        'rewrite'               => true,
        'rewrite_slug'          => '',        
    );
    register_post_type( 'press_article', $args );

    $meta_args = array(
        'type'         => 'string',
        'description'  => 'source',
        'single'       => true,
        'show_in_rest' => true,
    );

    register_post_meta( 'press_article', 'source', $meta_args );
    
}
add_action( 'init', 'generate_press_type', 0 );

I can see type "press" in the WP backend and create posts. When I query them the metafield shows up in the payload. I'm just wondering if its possible to get the field to show up in the Post editor, I see the list of custom fields but mine is not included:

Wonder if I missed an arg when registering either the post type or the meta? I looked at the docs and it seems I've got everything there but not sure...

Answer 1

You have to add custom metabox to show the field. Please check here - https://developer.wordpress.org/plugins/metadata/custom-meta-boxes/