How do I declare a @model in my view

I have a project called Billing. Inside, there is a folder called Models where my models are (only 2). One of them is called an invoice and I need to fill a table (bootstrap) with the data of this model. I need to do something like this, unless there is another way I still do not know:

@foreach(var item in Model)
{
   ........
}

So I need to declare the model in my View, right? I'm doing this:

@model IEnumerable<Fatura> and is giving this error:

  

The type or namespace name 'Invoice' could not be found (are you   missing a using directive or an assembly reference?)

If I put a @using ProjectName.PastaModels before, it gives the error:

  

Using directve is unnecessary

How do I use a model in my view to populate a table?

I did this on my controller

public class HomeController : Controller
    {
        // GET: Home

        private Conexao contexto = new Conexao();

        public ActionResult Index()
        {
            return View(contexto.Faturas.ToList());
        }
    }

And it says context is never assigned to...