How to add required attribute to a Django form field

@mariodev is correct. If you want a more elegant way to do this, refer to https://stackoverflow.com/a/37738828/2812260 (relevant part copied below):

If you really want to write elegant, DRY code, you should make a base form class that dynamically looks for all your required fields and modifies their widget required attribute for you (you can name it whatever you wish, but "BaseForm" seems apt):

from django.forms import ModelForm

class BaseForm(ModelForm):
    def __init__(self, *args, **kwargs):
        super(BaseForm, self).__init__(*args, **kwargs)
        for bound_field in self:
            if hasattr(bound_field, "field") and bound_field.field.required:
                bound_field.field.widget.attrs["required"] = "required"

And then have all your Form objects descend from it:

class UserForm(BaseForm):
    class Meta:
        model = User
        fields = []

    first_name = forms.CharField(required=True)
    last_name = forms.CharField(required=True)
    email = forms.EmailField(required=True, max_length=100)

If you want a declarative option on a per-form rather than a per-model basis this was my solution:

from django import forms

class RequiredFieldsModelForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(RequiredFieldsModelForm, self).__init__(*args, **kwargs)
        for bound_field in self:
            if (
                hasattr(bound_field, "field") and
                bound_field.name in self.Meta.required_fields
            ):
                bound_field.field.widget.attrs["required"] = "required"


# Your forms
class UserForm(RequiredFieldsModelForm):
    class Meta:
        required_fields = ['username']
        model = User

Just set required attribute to widget like this:

self.fields['field_name'].widget = forms.TextInput(attrs={'required':'required'})