Add Custom metabox(custom fields programatically) to Custom Post Types

/*============================= Custom Meta Box (Assign Articles) To Custom Post Type ============================ */
function assign_article_metabox() {
    $post_types = array( 'your-post-type' ); // you can use multiple post types here(array of post types)

    foreach ( $post_types as $post_type ) {

        add_meta_box(
            'member_sectionid',
            __( 'Name Of Metabox', 'member_textdomain' ),
            'assign_article_metafields',
            $post_type
        );
     }
}
add_action( 'add_meta_boxes', 'assign_article_metabox' );

function assign_article_metafields( $post ) {
    wp_nonce_field( 'assign_articles_savedata', 'article_meta_box_nonce' );
    $editor = explode( ',', get_post_meta( $post->ID, '_engaged_editors', true ) ); 
    $peerviewer = explode( ',', get_post_meta( $post->ID, '_engaged_peerviewers', true ) );?>
    <table class="form-table fh-profile-upload-options">
        <tr>
            <th><label for="twitter">Editors</label></th>
            <th><label for="twitter">Peer Viewers</label></th>
        </tr>
        <tr>
            <td>
               
                <select name="editors[]" id="editor" class="regular-text form-control-chosen" data-placeholder="Please select editors..." multiple>
                    <option>-- Select Editors --</option>             
                    <?php  
                        $editors = array(
                            'role'    => 'editor',
                            'orderby' => 'user_nicename',
                            'order'   => 'ASC'
                        );
                    $users_editors = get_users( $editors );                 
                    foreach( $users_editors as $user ): ?>                          
                        <option value="<?php echo $user->ID; ?>" <?php if(in_array($user->ID, $editor)) { echo "selected"; } ?>><?php echo esc_html( $user->display_name ); ?></option>
                    <?php endforeach; ?>
                </select>
                <br/>
                <span class="description">Please Select Editors.</span>
            </td>
       
            <td>
                <select name="peerviewers[]" id="editor_category" class="regular-text form-control-chosen" data-placeholder="Please select peerviewers..." multiple>
                    <option>-- Select Peerviewers --</option>             
                    <?php  
                        $peerviewers = array(
                            'role'    => 'peerviewer',
                            'orderby' => 'user_nicename',
                            'order'   => 'ASC'
                        );
                    $users_peerviewers = get_users( $peerviewers );                 
                    foreach( $users_peerviewers as $user ): ?>                          
                        <option value="<?php echo $user->ID; ?>" <?php if(in_array($user->ID, $peerviewer)) { echo "selected"; } ?>><?php echo esc_html( $user->display_name ); ?></option>
                    <?php endforeach; ?>
                </select>
                <br/>
                <span class="description">Please Select Peerviewers.</span>
            </td>
        </tr>
    </table>

    <?php
}

function assign_articles_savedata( $post_id ) {

         if ( ! isset( $_POST['article_meta_box_nonce'] ) ) {
            return;
         }
         
         if ( ! wp_verify_nonce( $_POST['article_meta_box_nonce'], 'assign_articles_savedata' ) ) {
            return;
         }

         if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
            return;
         }

         // Check the user's permissions.
         if ( isset( $_POST['post_type'] ) && 'page' == $_POST['post_type'] ) {

            if ( ! current_user_can( 'edit_page', $post_id ) ) {
                return;
            }

         } else {

            if ( ! current_user_can( 'edit_post', $post_id ) ) {
                return;
            }
         }

         if ( ! isset( $_POST['editors'] ) ) {
            return;
         }

         if ( ! isset( $_POST['peerviewers'] ) ) {
            return;
         }

         $editors =  implode(',', $_POST['editors'] );
         $peerviewers =  implode(',', $_POST['peerviewers'] );
         update_post_meta( $post_id, '_engaged_editors', $editors );
         update_post_meta( $post_id, '_editor_edited', '0' );
         update_post_meta( $post_id, '_engaged_peerviewers', $peerviewers );
}
add_action( 'save_post', 'assign_articles_savedata' );