diff --git a/docs/ecolyo/functionalities/initialization.md b/docs/ecolyo/functionalities/initialization.md
index 8d5550268cc75503701167080f65dc686dae0bd4..c3bfc13a27869d98649fdf0a34ca379e990533b2 100644
--- a/docs/ecolyo/functionalities/initialization.md
+++ b/docs/ecolyo/functionalities/initialization.md
@@ -53,3 +53,34 @@ You can see more on [cozy documentation](https://docs.cozy.io/en/cozy-doctypes/d
       }
     }
 ```
+
+### UserData creation
+
+We create a userData and store it in the couchDB under the doctype userData name '**com.grandlyon.ecolyo.userDataName'.** During this process, the objects related to the dataEntity will be be converted to an user version which contains informations about the user(example: user progress, the fluids connected and so on).
+
+To illustrate this, let's show an example of the conversion of quizEntity to userQuiz :
+
+```jsx
+DuelEntity {
+  id: string
+  title: string
+  description: string
+  duration: Duration
+}
+```
+
+Becomes :
+
+```jsx
+UserQuiz {
+  id: string
+  title: string
+  description: string
+	duration: Duration
+  threshold: number
+  state: UserDuelState
+  startDate: string | null
+  fluidTypes: FluidType[]
+  userConsumption: number
+}
+```