Code to Display Post ID Column in All Posts List WordPress Admin

/* Show Post ID Column in All Posts List WordPress */
function wpflt_get_post_id($defaults){
    $defaults['wps_post_id'] = __('ID');
    return $defaults;
}
function wpflt_post_id_column($column_name, $id){
    if($column_name === 'wps_post_id'){
        echo $id;
    }
}
add_filter('manage_posts_columns', 'wpflt_get_post_id', 5);
add_action('manage_posts_custom_column', 'wpflt_post_id_column', 5, 2);

By adding this code to your theme’s functions.php, a new column will be generated which shows the page ID of each post in All Posts list for WordPress Admin.