How to restore\find the admin menu item?

Question

PHP

Please tell me:
You need to choose a separate template for a separate page. when creating it, there should be a drop-down list with all the available options. In fact, I only have the choice of the parent page .
How it should be:
.
Like mine:

Answer 1

to create a template for the desired page, you need to: -
create a php file in the template theme, for example, page-shop.php
- at the beginning of the file write:
Shop Template will appear in the template drop-down list.
I hope I understood the question correctly.