diff --git a/docs/configuration/platform_configuration.md b/docs/configuration/platform_configuration.md
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+## Configuration for platform
+
+### Context
+- TwakeMail has actually been deployed on many different environments.
+
+### How to config
+
+1. Environments
+
+- `sass`: SaaS platform
+- `other`: Other platform
+
+2. Active field PLATFORM in [env.file](https://github.com/linagora/tmail-flutter/blob/master/env.file)
+```
+PLATFORM=saas
+```