diff --git a/sandwich-ktorfit/src/commonMain/kotlin/com/skydoves/sandwich/ktorfit/ApiResponseConverterFactory.kt b/sandwich-ktorfit/src/commonMain/kotlin/com/skydoves/sandwich/ktorfit/ApiResponseConverterFactory.kt
index 719c333..238901c 100644
--- a/sandwich-ktorfit/src/commonMain/kotlin/com/skydoves/sandwich/ktorfit/ApiResponseConverterFactory.kt
+++ b/sandwich-ktorfit/src/commonMain/kotlin/com/skydoves/sandwich/ktorfit/ApiResponseConverterFactory.kt
@@ -63,6 +63,17 @@ public class ApiResponseConverterFactory internal constructor() : Converter.Fact
 
   public companion object {
     @JvmStatic
+    /**
+     * Transforms the sign-up request data to match the backend's expected format.
+     *
+     * @param {SignUpRequest} signUpData - The original sign-up request data.
+     *
+     * @returns {Object} The transformed sign-up request data with the following changes:
+     * - `firstName` is mapped to `first_name`
+     * - `lastName` is mapped to `last_name`
+     * - `email` is mapped to `username`
+     * - All other properties remain unchanged.
+     */
     public fun create(): ApiResponseConverterFactory {
       return ApiResponseConverterFactory()