As WordPress is an open source CMS (Content Management System), the WordPress community provides a lot of FREE documentation for beginners and advanced users alike. Here is a very useful WordPress reference article about how to find the WordPress Page ID within the backend admin area
Locating the page with the ID already known:
You can learn that in order to find out the WordPress page ID for any given WordPress page that you are working on, all you need to do is simply enter into your browser address bar: “http://www.yoursite.com/?page_id=” [replacing ” www.yoursite.com ” with your actual site URL, and “?page_id=” with the WordPress page ID (that you would like to find out)], just before the WordPress page URL that you have browsed to.
For example, if you were working on WordPress Page ID #1000 in WordPress backend, then you should enter into your browser address bar: http://www.yoursite.com/?page_id=1000. The WordPress page query parameter will automatically be used to search for the WordPress page in WordPress backend.
So if a WordPress custom post type was specified in the WordPress Page URL as an example, and instead of http://www.yoursite.com/?page_id=1000 , it was typed into the browser address bar as http://www.yoursite.com/products/my-product/?page_id=1000 , then WordPress backend would assume that you wanted to find out more about WordPress Page ID # 1000 within WordPress Post Type: Products . That’s what I mean by using “?page_id=” at the end of any WordPress Page URL in order to get its corresponding WordPress page ID number.
Finding out the Page ID where it is not known:
Once you’re in the admin area, navigate to “Pages” > All Pages and source the one you’d like to find the ID of.
Remaining on this page, hover over the page in question and in the left corner you will see a URL.
You are looking for a number. This is the PAGE ID for that given page.
In the example below, the PAGE ID is 81445.