[Area 1] Notify MS 365 users (#21160)

* [Area 1] Add note to MS 365 onboarding

* create page and update note

* Update src/content/docs/email-security/email-security-integration.mdx

Co-authored-by: Patricia Santa Ana <[email protected]>

---------

Co-authored-by: Patricia Santa Ana <[email protected]>

Author: Maddy-Cloudflare

src/content/docs/email-security/email-security-integration.mdx

@@ -0,0 +1,17 @@
+---
+title: Zero Trust Email Security integration
+pcx_content_type: how-to
+sidebar:
+  order: 8
+
+---
+
+[Zero Trust Email Security](/cloudflare-one/email-security/) users must delete their domains from the Area 1 portal before using [Microsoft API deployment](/cloudflare-one/email-security/setup/post-delivery-deployment/api/) in Zero Trust Email Security, and complete the onboarding process in the Zero Trust dashboard. Once your new domain has been onboarded, all the information will be automatically updated.
+
+To delete your domain(s) from the Area 1 portal:
+
+1. Log in to the [Area 1 portal](https://horizon.area1security.com/).
+2. Select **Settings** (the gear icon).
+3. In **Email Configuration** > **Domains & Routing**.
+4. Go to the domain you want to delete, select the three dots, then select **Delete**.
+5. Refer to [Enable Email Security via the dashboard](https://developers.cloudflare.com/cloudflare-one/email-security/setup/post-delivery-deployment/api/office365-api/#enable-email-security-via-the-dashboard) to initiate the onboarding process for API deployment.