[DOCS] Add custom fields to cases (#4070)

Co-authored-by: Nastasha Solomon <[email protected]>

docs/cases/cases-manage.asciidoc

@@ -37,6 +37,44 @@ NOTE: If you've selected a connector for the case, the case is automatically pus
 image::images/cases-ui-open.png[Shows an open case]
 // NOTE: This is an autogenerated screenshot. Do not edit it directly.
 
+[float]
+[[cases-ui-custom-fields]]
+== Add custom fields
+
+preview::[]
+
+You can add optional and required fields for customized case collaboration.
+
+. Go to *Cases* and click *Settings*.
++
+--
+[role="screenshot"]
+image::images/cases-custom-field-settings.png[View custom fields in case settings]
+// NOTE: This is an autogenerated screenshot. Do not edit it directly.
+
+NOTE: To view and change case settings, you must have the appropriate {kib} feature privileges. Refer to <<case-permissions>>.
+--
+
+. In the *Custom fields* section, click *Add field*.
++
+--
+[role="screenshot"]
+image::images/cases-add-custom-field.png[Add a custom field in case settings]
+// NOTE: This is an autogenerated screenshot. Do not edit it directly.
+--
+
+. Enter a field label.
+
+. Choose a field type: text or toggle.
+
+. (Optional) To make the text field mandatory, select *Make this field required*.
+
+. Click *Save field*.
+
+After you create custom fields, they're added to all new and existing cases.
+Existing cases have null values for the new text fields until you set them.
+To manage custom fields, go to the *Settings* page and remove or edit them.
+
 [float]
 [[cases-ui-notifications]]
 == Add email notifications
@@ -46,8 +84,7 @@ cases.
 
 For hosted {kib} on {ess}:
 
-. Add the email addresses to the monitoring email allowlist. Follow the steps in
-{cloud}/ec-watcher.html#ec-watcher-allowlist[Send alerts by email].
+. Add the email domains to the {cloud}/ec-organizations-notifications-domain-allowlist.html[notifications domain allowlist].
 +
 --
 You do not need to take any more steps to configure an email connector or update

docs/getting-started/cases-req.asciidoc

@@ -29,7 +29,7 @@ To grant access to cases, set the {kib} space privileges for the *Cases* and *{c
 |==============================================
 
 | Action      | {kib} Privileges
-| Give full access to manage cases
+| Give full access to manage cases and settings
 a|
 * **All** for the *Cases* feature under *Security*
 * **All** for the *{connectors-feature}* feature under *Management*