Added details about seat usage and the users it applies to

doc/subscriptions/gitlab_com/index.md

@@ -91,21 +91,34 @@ The following table describes details of your subscription:
 > - [Updated](https://gitlab.com/gitlab-org/gitlab/-/issues/292086) in GitLab 13.8 to include public
     email address.
 
-To view a list of seats being used, go to **Settings > Billing**.
-Under **Seats currently in use**, select **See usage**.
-
-You can also see this information in your group settings by going to **Menu > Groups > Your Group > Settings > Usage Quotas**, and the information about **Seat usage** will be under the **Seats** tab.
-
 The **Seat usage** page lists all users occupying seats. Details for each user include:
 
 - Full name
 - Username
 - Public email address (if they have provided one in their [user settings](../../user/profile/index.md#access-your-user-settings))
 
-The Seat usage listing is updated live, but the usage statistics on the billing page are updated
+The seat usage listing is updated live, but the usage statistics on the billing page are updated
 only once per day. For this reason there can be a minor difference between the seat usage listing
 and the billing page.
 
+Every user is included in seat usage, with the following exceptions:
+
+- Users who are pending approval.
+- Members with the Guest role on an Ultimate subscription.
+- Users without project or group memberships on an Ultimate subscription.
+- GitLab-created service accounts: `Ghost User` and bots
+  ([`Support Bot`](../../user/project/service_desk.md#support-bot-user),
+  [`Project bot users`](../../user/project/settings/project_access_tokens.md#project-bot-users), and
+  so on.)
+
+### View seat usage
+
+To view a list of seats being used:
+
+1. On the top bar, select **Menu > Groups** and find your group.
+1. On the left sidebar, select **Settings > Usage Quotas**.
+1. Under the **Seats** tab, view usage information.
+
 ### Search seat usage
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/262875) in GitLab 13.8.