Templates may have been created for specific content. In your list of all templates, for example, you’ll see an “All Archives” template that is used only in the Archives section and therefore cannot be assigned to any page.
Therefore, in the template selection for a page, you’ll only see templates that can also be used for the single-page view.
As @threadi mentioned when you’re editing a page in the block editor, the “Template” dropdown only shows templates that are meant for pages.
Read more about this here: https://wordpress.org/documentation/article/template-editor/
https://snipboard.io/jTC9MK.jpg
to be honest i am so confuse to understand template ,how i use index template
Take a bit to go through the link I sent, you’ll see it covers exactly what you’re asking about.
Also, this guide breaks down how templates work inside the Site Editor: https://wordpress.org/documentation/article/site-editor/
You should take time to learn this stuff properly.
@asadzafar007 Your duplicate topics have been removed. Please stop creating topics about the same thing.