это простой пример
views.py
def test_form(request):
if request.method == "POST":
user = request.POST.get('username')
if user == "mark":
return HttpResponse('hello mark')
return render(request, "form.html")
urls.py
path ('form/', test_form, name="form")
form. html
<form method="POST" action="{% url 'form' %}">{% csrf_token %}
<input type="text" name="username">
<input type="submit" name="submit">
</form>