interface ApiInterface {

@Multipart
@POST("/")
suspend fun getRendomFact(
    @Part("secret_key") secretKey: String,
    @Part("token") token: String,
    @Part("action") action: String
): Response<HomeData>

}

URL here

object Util {
    const val Base = "https://example.com/guruji_apis/v1/index.php/"
}

Retrofit instance here

object RetrofitInstance {
    val api : ApiInterface by lazy {
        Retrofit.Builder()
            .baseUrl(Util.Base)
            .addConverterFactory(GsonConverterFactory.create())
            .build()
            .create(ApiInterface::class.java)
    }
}

This code is in main activity and calls when we click on button

 fun sendResponse() {
        GlobalScope.launch(Dispatchers.IO) {

            val response = try {
                RetrofitInstance.api.getRendomFact(
                    secretKey = "asdfghjkl12345",
                    token = "eyJ0R86Yz6XA8u_4",
                    action = "get_home_screen")
            } catch (e: HttpException) {
                Log.d("arvind,ex", "sendResponse: ${e}")
                return@launch
            } catch (e: IOException) {
                Log.d("arvind,ioex", "sendResponse: ${e}")
                return@launch
            }
            if (response.isSuccessful && response.body() != null) {
                withContext(Dispatchers.Main) {
                    Log.d("arvind", "sendResponse: ${response.body()}")

                }
            }
            else{
                Log.d("arvind", "sendResponse: ${response}")
            }
        }
    }
}

In this above code i have provided not working in form data and i am using this API doesn’t have any end point because we are calling it directly by sending action which is different for different data,
and using latest version of android studio and dependencies also