How do I enable the template selection in the WordPress toolbar when developing a custom theme?

In WordPress, a custom page template allows you to create different layouts or designs for specific pages on your website. This customization allows you to choose a specific template for a page in the admin area, providing flexibility in how content is displayed.

<?php
/*
 * Template Name: Template Name
 * */

1. /* … */: This is a PHP comment block. Comments in PHP are text
   that are not executed and are used for providing explanations or
   notes within the code.
2. Template Name: Template Name: This is a special comment used in
   WordPress to define a custom page template. By adding this comment
   block at the beginning of a PHP file within your WordPress theme,
   you’re telling WordPress that this file can be used as a custom
   template for pages. The "Template Name" is the name that will be
   displayed in the WordPress admin area when selecting a template for
   a page.
   For instance, if you have a file named custom-template.php and it contains the code you provided, when you create or edit a page in WordPress, under the Page Attributes section, you’ll see a Template dropdown where "Template Name" will appear as an option for selecting this custom template for that specific page.

As for your goal of creating a custom theme with the ability to select page templates in the admin area, ensure the following:

1. File Placement: Place your custom page template files within your
   WordPress theme directory.
2. Proper Comment Block: Include the comment block Template Name:
   YourTemplate at the top of each PHP file that you want to designate
   as a custom template.
3. WordPress Admin Area: When creating or editing a page in WordPress,
   look for the "Page Attributes" metabox. There, you should see a
   "Template" dropdown displaying the names of your custom templates.
   Select the appropriate template for the page you’re editing.