To use this module, you need to:

1.  Go to **Sales \> Products \> Products** and create a **service**
    product.

2.  Within the product, choose your preferences under **General
    Information** tab, as follows:

    - From **Create on Order** select *Task* or *Project & Task*.
    - Tick off **Invoicing control by task** checkbox, and save.

    ![image](static/description/product_view_invoicefinishedtask2.png)

3.  Go to **Sales \> Orders \> Orders** and create a new one. Add a
    customer and the product you have created.

4.  Confirm the sales order. It will create a new task on your selected
    project.

5.  Go to the task and you will find a smartbutton named *Not
    invoiceable*. When you click on it, you will indicate that the task
    can be invoiced.

    ![image](static/description/task_view_invoicefinishedtask2.png)

    If the product is configured with an invoicing policy "Timesheets on
    tasks", time spent on the task is used to compute the delivered
    quantity.

6.  Optional: if you want to use project stages to control this, go to
    **Project \> Configuration \> Task Stages**, and in the stages that
    you consider are invoiceable, you have to set the *Invoiceable*
    field to true.