diff --git a/lib/rent_cars/cars.ex b/lib/rent_cars/cars.ex
index da5dde5..30814c2 100644
--- a/lib/rent_cars/cars.ex
+++ b/lib/rent_cars/cars.ex
@@ -2,9 +2,18 @@ defmodule RentCars.Cars do
   alias __MODULE__.Car
   alias RentCars.Repo
 
+  def get_car!(id), do: Repo.get!(Car, id)
+
   def create(attrs) do
     %Car{}
     |> Car.changeset(attrs)
     |> Repo.insert()
   end
+
+  def update(car_id, attrs) do
+    car_id
+    |> get_car!()
+    |> Car.update_changeset(attrs)
+    |> Repo.update()
+  end
 end
diff --git a/lib/rent_cars/cars/car.ex b/lib/rent_cars/cars/car.ex
index e50836d..dd5a62b 100644
--- a/lib/rent_cars/cars/car.ex
+++ b/lib/rent_cars/cars/car.ex
@@ -7,20 +7,19 @@ defmodule RentCars.Cars.Car do
 
   @primary_key {:id, :binary_id, autogenerate: true}
   @foreign_key_type :binary_id
-  @fields ~w/ available brand daily_rate description fine_amount license_plate name category_id/a
-
+  @fields ~w/available brand daily_rate description fine_amount license_plate name category_id/a
   schema "cars" do
-    field :name, :string
-    field :description, :string
     field :available, :boolean, default: true
     field :brand, :string
     field :daily_rate, :integer
+    field :description, :string
     field :fine_amount, :integer
     field :license_plate, :string
+    field :name, :string
     belongs_to :category, Category
     many_to_many :specifications, Specification, join_through: CarSpecification
 
-    timestamps(type: :utc_datetime)
+    timestamps()
   end
 
   @doc false
@@ -32,4 +31,16 @@ defmodule RentCars.Cars.Car do
     |> unique_constraint(:license_plate)
     |> cast_assoc(:specifications, with: &Specification.changeset/2)
   end
+
+  def update_changeset(car, attrs) do
+    car
+    |> changeset(attrs)
+    |> validate_change(:license_plate, fn :license_plate, license_plate ->
+      if car.license_plate != license_plate do
+        [license_plate: "you can`t update license_plate"]
+      else
+        []
+      end
+    end)
+  end
 end
diff --git a/lib/rent_cars/cars/car_specification.ex b/lib/rent_cars/cars/car_specification.ex
index 64df197..fa5cad6 100644
--- a/lib/rent_cars/cars/car_specification.ex
+++ b/lib/rent_cars/cars/car_specification.ex
@@ -1,22 +1,22 @@
 defmodule RentCars.Cars.CarSpecification do
-  use Ecto.Schema
-  import Ecto.Changeset
-  alias RentCars.Cars.Car
-  alias RentCars.Specifications.Specification
+   use Ecto.Schema
+   import Ecto.Changeset
+   alias RentCars.Cars.Car
+   alias RentCars.Specifications.Specification
 
-  @primary_key {:id, :binary_id, autogenerate: true}
-  @foreign_key_type :binary_id
-  schema "cars_specifications" do
-    belongs_to(:car, Car)
-    belongs_to(:specification, Specification)
+   @primary_key {:id, :binary_id, autogenerate: true}
+   @foreign_key_type :binary_id
+   schema "cars_specifications" do
+     belongs_to :car, Car
+     belongs_to :specification, Specification
 
     timestamps(type: :utc_datetime)
   end
 
-  @doc false
-  def changeset(car_specification, attrs) do
-    car_specification
-    |> cast(attrs, [])
-    |> validate_required([])
-  end
-end
+   @doc false
+   def changeset(car_specification, attrs) do
+     car_specification
+     |> cast(attrs, [])
+     |> validate_required([])
+   end
+ end
diff --git a/priv/repo/migrations/20240108111318_create_cars.exs b/priv/repo/migrations/20240108111318_create_cars.exs
index 32b1418..282b037 100644
--- a/priv/repo/migrations/20240108111318_create_cars.exs
+++ b/priv/repo/migrations/20240108111318_create_cars.exs
@@ -23,7 +23,6 @@ defmodule RentCars.Repo.Migrations.CreateCars do
     end
 
     create unique_index(:cars, [:license_plate])
-
     create index(:cars, [:category_id])
   end
 end
diff --git a/test/rent_cars/cars_test.exs b/test/rent_cars/cars_test.exs
index 8e6951d..384ba0e 100644
--- a/test/rent_cars/cars_test.exs
+++ b/test/rent_cars/cars_test.exs
@@ -2,6 +2,7 @@ defmodule RentCars.CarsTest do
   use RentCars.DataCase
   alias RentCars.Cars
   import RentCars.CategoriesFixtures
+  import RentCars.CarsFixtures
 
   test "create car with success" do
     category = category_fixture()
@@ -51,4 +52,18 @@ defmodule RentCars.CarsTest do
       end
     )
   end
+
+  test "update a car with success" do
+    car = car_fixture()
+    payload = %{name: "Lancer 2023"}
+    assert {:ok, car} = Cars.update(car.id, payload)
+    assert car.name == payload.name
+  end
+
+  test "throw error when try updating the licence_plate" do
+    car = car_fixture()
+    payload = %{license_plate: "update license_plate"}
+    assert {:error, changeset} = Cars.update(car.id, payload)
+    assert "you can`t update license_plate" in errors_on(changeset).license_plate
+  end
 end
diff --git a/test/support/fixtures/cars_fixtures.ex b/test/support/fixtures/cars_fixtures.ex
new file mode 100644
index 0000000..fc833fe
--- /dev/null
+++ b/test/support/fixtures/cars_fixtures.ex
@@ -0,0 +1,48 @@
+defmodule RentCars.CarsFixtures do
+  alias RentCars.Cars
+  import RentCars.CategoriesFixtures
+
+  def car_attrs(attrs \\ %{}) do
+    category = category_fixture()
+
+    valid_attrs =
+      %{
+        name: "Honda City",
+        description: "Good car",
+        brand: "Honda",
+        daily_rate: 100,
+        license_plate: "adfdf #{:rand.uniform(10_000)}",
+        fine_amount: 30,
+        category_id: category.id,
+        specifications: [
+          %{
+            name: "wheels",
+            description: "4 wheels"
+          },
+          %{
+            name: "steering",
+            description: "electric"
+          },
+          %{
+            name: "navigation",
+            description: "navigation included"
+          },
+          %{
+            name: "cruze control",
+            description: "cruze control included"
+          }
+        ]
+      }
+
+    Enum.into(attrs, valid_attrs)
+  end
+
+  def car_fixture(attrs \\ %{}) do
+    {:ok, car} =
+      attrs
+      |> car_attrs()
+      |> Cars.create()
+
+    car
+  end
+end