def checkout(request):
    form = CheckoutForm()
    if request.method == "POST":
        form = CheckoutForm(request.POST)
        if form.is_valid():
            send_mail('Mountain shop list', 'bbbbbbbbb', 'testuserbobtilly@ukr.net', [form.cleaned_data['email']],
                      fail_silently=False)
    return render(request, "checkout.html", {"form": form})


settings.py
EMAIL_HOST = 'smtp.ukr.net'
EMAIL_PORT = 2525
EMAIL_HOST_USER = 'testuserbobtilly@ukr.net'
EMAIL_HOST_PASSWORD = 'пароль от емейла'
EMAIL_USE_TLS = False