[April 6] Update Pages for new workflow and www variant settings (#17737)

* add first pass edits to support new pages settings

/cc github/pages-engineering#383

* update with reusable

* update with new step

* fix break

* update with www vvarient info

* update with latest

* apply feedback

* unversion

* typo

* update versioning to make it render

* update a few screenshots

* update with remove

* Apply suggestions from code review

Co-authored-by: Laura Coursen <lecoursen@github.com>

Co-authored-by: Meg Bird <megbird@github.com>
Co-authored-by: Melanie Yarbrough <11952755+myarb@users.noreply.github.com>
Co-authored-by: Laura Coursen <lecoursen@github.com>

Author: 4 people

assets/images/help/pages/choose-a-theme.png

@@ -24,7 +24,9 @@ topics:
 | Custom subdomain | `blog.example.com` |
 | Apex domain        | `example.com` |
 
-You can set up either or both types of custom domains for your site. We recommend always using a `www` subdomain, even if you also use an apex domain. For more information, see "[Using an apex domain for your {% data variables.product.prodname_pages %} site](#using-an-apex-domain-for-your-github-pages-site)."
+You can set up either or both of apex and `www` subdomain configurations for your site. For more information on apex domains, see "[Using an apex domain for your {% data variables.product.prodname_pages %} site](#using-an-apex-domain-for-your-github-pages-site)."
+
+We recommend always using a `www` subdomain, even if you also use an apex domain. When you create a new site with an apex domain, we automatically attempt to secure the `www` subdomain for use when serving your site's content. If you configure a `www` subdomain, we automatically attempt to secure the associated apex domain. For more information, see "[Managing a custom domain for your {% data variables.product.prodname_pages %} site](/articles/managing-a-custom-domain-for-your-github-pages-site)."
 
 After you configure a custom domain for a user or organization site, the custom domain will replace the `<user>.github.io` or `<organization>.github.io` portion of the URL for any project sites owned by the account that do not have a custom domain configured. For example, if the custom domain for your user site is `www.octocat.com`, and you have a project site with no custom domain configured that is published from a repository called `octo-project`, the {% data variables.product.prodname_pages %} site for that repository will be available at `www.octocat.com/octo-project`.
 
@@ -38,11 +40,11 @@ Subdomains are configured with a `CNAME` record through your DNS provider. For m
 
 A `www` subdomain is the most commonly used type of subdomain. For example, `www.example.com` includes a `www` subdomain.
 
-`www` subdomains are the most stable type of custom domain because `www` subdomains are not affected by changes to the IP addresses of {% data variables.product.product_name %}'s servers. Your site will also load faster because Denial of Service (DoS) attack protection can be implemented more efficiently.
+`www` subdomains are the most stable type of custom domain because `www` subdomains are not affected by changes to the IP addresses of {% data variables.product.product_name %}'s servers.
 
 #### Custom subdomains
 
-A custom subdomain is a type of subdomain that doesn't use the standard `www` subdomain. Custom subdomains are mostly used when you want two distinct sections of your site. For example, you can create a site called `blog.example.com` and customize that section independently from `www.example.com`.
+A custom subdomain is a type of subdomain that doesn't use the standard `www` variant. Custom subdomains are mostly used when you want two distinct sections of your site. For example, you can create a site called `blog.example.com` and customize that section independently from `www.example.com`.
 
 ### Using an apex domain for your {% data variables.product.prodname_pages %} site
 

assets/images/help/pages/click-private-pages-url-to-preview.png

@@ -42,6 +42,7 @@ To set up a `www` or custom subdomain, such as `www.example.com` or `blog.exampl
 
 {% data reusables.pages.navigate-site-repo %}
 {% data reusables.repositories.sidebar-settings %}
+{% data reusables.pages.sidebar-pages %}
 4. Under "Custom domain", type your custom domain, then click **Save**. This will create a commit that adds a _CNAME_ file in the root of your publishing source.
   ![Save custom domain button](/assets/images/help/pages/save-custom-subdomain.png)
 5. Navigate to your DNS provider and create a `CNAME` record that points your subdomain to the default domain for your site. For example, if you want to use the subdomain `www.example.com` for your user site, create a `CNAME` record that points `www.example.com` to `<user>.github.io`. If you want to use the subdomain `www.anotherexample.com` for your organization site, create a `CNAME` record that points `www.anotherexample.com` to `<organization>.github.io`. The `CNAME` record should always point to `<user>.github.io` or `<organization>.github.io`, excluding the repository name. {% data reusables.pages.contact-dns-provider %} {% data reusables.pages.default-domain-information %}
@@ -67,6 +68,7 @@ To set up an apex domain, such as `example.com`, you must configure a _CNAME_ fi
 
 {% data reusables.pages.navigate-site-repo %}
 {% data reusables.repositories.sidebar-settings %}
+{% data reusables.pages.sidebar-pages %}
 4. Under "Custom domain", type your custom domain, then click **Save**. This will create a commit that adds a _CNAME_ file in the root of your publishing source.
   ![Save custom domain button](/assets/images/help/pages/save-custom-apex-domain.png)
 5. Navigate to your DNS provider and create either an `ALIAS`, `ANAME`, or `A` record. {% data reusables.pages.contact-dns-provider %}
@@ -92,6 +94,31 @@ To set up an apex domain, such as `example.com`, you must configure a _CNAME_ fi
 {% data reusables.pages.build-locally-download-cname %}
 {% data reusables.pages.enforce-https-custom-domain %}
 
+### Configuring an apex domain and the `www` subdomain variant
+
+When using an apex domain, we recommend configuring your {% data variables.product.prodname_pages %} site to host content at both the apex domain and that domain's `www` subdomain variant.
+
+To set up a `www` subdomain alongside the apex domain, you must first configure an apex domain, which will create an `ALIAS`, `ANAME`, or `A` record with your DNS provider. For more information, see "[Configuring an apex domain](#configuring-an-apex-domain)."
+
+After you configure the apex domain, you must to configure a CNAME record with your DNS provider.
+
+1. Navigate to your DNS provider and create a `CNAME` record that points `www.example.com` to the default domain for your site: `<user>.github.io` or `<organization>.github.io`. Do not include the repository name. {% data reusables.pages.contact-dns-provider %} {% data reusables.pages.default-domain-information %}
+2. To confirm that your DNS record configured correctly, use the `dig` command, replacing _WWW.EXAMPLE.COM_ with your `www` subdomain variant.
+```shell
+    $ dig <em>WWW.EXAMPLE.COM</em> +nostats +nocomments +nocmd
+    > ;<em>WWW.EXAMPLE.COM.</em>                     IN      A
+    > <em>WWW.EXAMPLE.COM.</em>              3592    IN      CNAME   <em>YOUR-USERNAME</em>.github.io.
+    > <em>YOUR-USERNAME</em>.github.io.      43192   IN      CNAME   <em> GITHUB-PAGES-SERVER </em>.
+    > <em> GITHUB-PAGES-SERVER </em>.         22      IN      A       192.0.2.1
+```
+### Removing a custom domain
+
+{% data reusables.pages.navigate-site-repo %}
+{% data reusables.repositories.sidebar-settings %}
+{% data reusables.pages.sidebar-pages %}
+4. Under "Custom domain," click **Remove**.
+  ![Save custom domain button](/assets/images/help/pages/remove-custom-domain.png)
+
 ### Further reading
 
 - "[Troubleshooting custom domains and {% data variables.product.prodname_pages %}](/articles/troubleshooting-custom-domains-and-github-pages)"