Fix environment variables

Author: Ndpnt

content/collections/reference/environment-variables.md

@@ -3,11 +3,13 @@ title: Environment Variables
 weight: 4
 ---
 
-## Environment Variables
+## Environment variables
 
-Environment variables can be used to configure sensitive information:
+This reference documentation details all available environment variables that can be used to configure sensitive information.
 
-{{< configOption name="OTA_ENGINE_SMTP_PASSWORD" type="string" description="SMTP password for email notifications." >}}
+### Engine
+
+{{< configOption name="OTA_ENGINE_SMTP_PASSWORD" type="string" description="SMTP password for email error notifications." >}}
 
 {{< configOption name="OTA_ENGINE_SENDINBLUE_API_KEY" type="string" description="API key for SendInBlue." >}}
 
@@ -16,3 +18,9 @@ Environment variables can be used to configure sensitive information:
 {{< configOption name="OTA_ENGINE_GITLAB_TOKEN" type="string" description="GitLab token for API access." >}}
 
 {{< configOption name="OTA_ENGINE_GITLAB_RELEASES_TOKEN" type="string" description="GitLab token for dataset releases." >}}
+
+---
+
+### Federation API 
+
+{{< configOption name="OTA_FEDERATION_API_SMTP_PASSWORD" type="string" description="SMTP password for email error notifications." >}}