To complete this recipe, execute the following steps:

1. Add a new forms.py file with the message form containing two fields: the recipient selection and message text. Also, this form will have an initialization method, which will accept the request object, and then modify QuerySet for the recipient's selection field:

# email_messages/forms.py
from django import forms
from django.contrib.auth.models import User
from django.utils.translation import ugettext_lazy as _


class MessageForm(forms.Form):
    recipient = forms.ModelChoiceField(
        label=_("Recipient"),
        queryset=User.objects.all(),
        required=True)
    message = forms.CharField(
        label=_("Message"),
        widget=forms.Textarea,
        required=True)

    def __init__(self, request, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.request = request
        self.fields["recipient"].queryset = (
            self.fields["recipient"].queryset.exclude(
                pk=request.user.pk))

2. Create views.py with the message_to_user() and message_sent() view functions in order to handle the form. As you can see, the request object is passed as the first parameter to the form, as follows:

# email_messages/views.py
from django.contrib.auth.decorators import login_required
from django.shortcuts import render, redirect

from .forms import MessageForm


@login_required
def message_to_user(request):
    if request.method == "POST":
        form = MessageForm(request, data=request.POST)
        if form.is_valid():
            # do something with the form
            return redirect("message_sent")
    else:
        form = MessageForm(request)

    return render(request,
                  "email_messages/message_to_user.html",
                  {"form": form})


@login_required
def message_sent(request):
    return render(request,
                  "email_messages/message_sent.html")

3. Add a very basic template for the message form under templates/email_messages/message_to_user.html, as in the following:

{# email_messages/message_to_user.html #}
<form action="">
    {{ form.as_p }}
</form>

4. We need the template for when the message has been sent. Again, we define it here at templates/email_messages/message_sent.html with minimal content for demonstration:

{# email_messages/message_sent.html #}
<p>Thanks for sending your note!</p>

5. Additionally, we need to wire up the URLs so that Django will know how to route the requests properly. First, we will create email_messages/urls.py, as follows:

# email_messages/urls.py
from django.urls import path

from .views import message_to_user, message_sent

urlpatterns = [
    path('/', message_to_user, 'message_to_user'),
    path('sent/', message_sent, 'message_sent'),
]

6. We need to include these patterns in our urls.py project:

# project/urls.py
from django.urls import include, path

urlpatterns = [
    # ...
    path('email/', include('email_messages.urls')),
]