change format of date type input field code example
Example 1: how to set a date for type date inpt
<input type="date" id="start" name="trip-start" value="2018-07-22">
Example 2: DateTimeField change format
class UserSerializer(serializers.ModelSerializer):
date_joined = serializers.DateTimeField(format="<Your format>")
class Meta:
model = User
fields = ('username', 'email', 'first_name', 'last_name', 'is_superuser', 'is_staff', 'is_active','get_absolute_url')