Q:

AttributeError: 'UserMF' object has no attribute 'id'

In the models.py, please attent there I did not give the id in User model:
class User(models.Model):
    username = models.CharField(max_length=16)
    password = models.CharField(max_length=16)
    ...

In the ModelForm, I put the id in the UserFM:
class UserMF(ModelForm):

    class Meta:
        model = models.User
        fields = ('id', 'username', 'password', 'phone', 'email') 

When I get the user's id, I will get the bellow error:

AttributeError: 'UserMF' object has no attribute 'id'

How to solve this issue, who can help me with that? 

EDIT
When I get the id, the method is bellow:
obj = UserMF(request.POST)

if obj.is_valid():
    obj.save()
    xxx = obj.id

A:

Read the error more closely; it is telling you that the form has no such attribute, which it doesn't.
In order to get a User object from a UserMF instance, you need to validate and save it.
form = UserMF(request.POST)
if form.is_valid()
    obj = form.save()

