From WordPress version 3.0, we can add custom templates for the single display of posts belonging to custom post types.
From version 3.1, WordPress added support for custom templates for archive displays.
How does Template Hierarchy scan the Custom Post Type template files?
WordPress will work through the template hierarchy and use the template file it comes across first.
For example, if you want to create a custom template file for custom post type “projects”, make a single-projects.php.
single-custom_post_type.php > single.php
👉 If you don’t want to create custom template files, WordPress will use archive.php. single.php and index.php files.
Basically,
- single posts of a custom post type will use single-{post_type}.php
- single posts of a custom post type archives will use archive-{post_type}.php
👉 If you don’t have this post type archive page you can pass BLOG_URL?post_type={post_type}
where {post_type} is the $post_type argument of the register_post_type() function.
So for the above example, you could create single-projects.php and archive-projects.php template files for single product posts and their archives.
👉 Alternatively, you can use the is_post_type_archive() function in any template file to check if the query shows an archive page of a given post types(s), and the post_type_archive_title() to display the post type title.
Custom Post Type templates
single-{post-type}.php
The single post template used when a visitor requests a single post from a custom post type.
For example, single-projects.php would be used for displaying single posts from a custom post type named projects.
archive-{post-type}.php
The archive post type template is used when visitors request a custom post type archive.
For example, archive-projects.php would be used for displaying an archive of posts from the custom post type named projects.
The archive.php template file is used if the archive-{post-type}.php is not present.
index.php
The index.php is used if any of the following query template for the custom post type is not present.
- single-{post-type}.php,
- single.php,
- archive-{post-type}.php,
- archive.php,
- search.php
You can read more on developers.wordpress.com
archive-page custom file hierarchy post type single-page template