I'm new to Django, but I took a peek into the code and this seems to be the way to have a password field using form fields:

class AuthForm(forms.Form):
    username  = forms.CharField(label="Your Username" )
    pw = forms.CharField( widget=forms.PasswordInput, label="Your Password" )
 

(Note from someone else: Be aware that this will not validate your password to ensure it has only alpha-numeric values. This could have 50 spaces for a password.)

(Note from OP - That's OK. There is no good reason why so many developers limit passwords to only a subset of ASCII characters.)